Армирование стяжки сп: СП 29.13330.2011 Полы. Актуализированная редакция СНиП 2.03.13-88 (с Изменением N 1)

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8. Стяжка (основание под покрытие)

8.1 Стяжка предусматриваться, когда необходимо:

• выравнивание поверхности нижележащего слоя; укрытие трубопровода;
• распределение нагрузок по теплозвукоизоляционным слоям;
• обеспечение нормируемого теплоусвоения полов;
• создание уклонов на полах по перекрытиям.

8.2 Наименьшая толщина цементно-песчаной или бетонной стяжки, для создания уклона в местах примыкания к сточным лоткам, каналам и трапам может быть: при укладке ее по плитам перекрытия – 30 мм, по тепло- и звукоизолирующему слою – 40 мм. Толщина стяжки для укрытия трубопроводов (в том числе и в обогреваемых полах) делается не менее чем на 45 мм больше диаметра трубопроводов.СП 29.13330.2011

Минимальная толщина слоя цементно песчаной стяжки может быть не менее 30 мм

8.3 Для выравнивания поверхности нижележащего слоя и укрытия трубопроводов, а также для создания уклона на перекрытии предусматриваются монолитные стяжки из бетона класса не ниже В12,5 или из цементно-песчаных растворов на основе смесей сухих строительных напольных на цементном вяжущем с прочностью на сжатие не ниже 15 МПа.

8.4 Под наливные полимерные покрытия монолитные стяжки выполняются из бетона класса не ниже В15 или из цементно песчаных растворов из смесей сухих строительных напольных на цементном вяжущем с прочностью на сжатие не ниже 20 МПа.

8.5 Стяжки, укладываемые по упругому тепло- и звукоизолирующему слою, предусматриваться из бетона класса не ниже В15 или из цементно-песчаных растворов из смесей сухих строительных напольных на цементном вяжущем с прочностью на сжатие не ниже 20 МПа.

8.6 Толщина стяжки с охлаждающими трубками в плите катков с искусственным льдом составляет 140 мм.

8.7 Толщина монолитных стяжек из дисперсно-самоуплотняющихся растворов на базе сухих смесей строительных напольных с цементным вяжущим, применяемых для выравнивания поверхности нижележащего слоя, выполняется не менее 1,5 диаметра максимального наполнителя, содержащегося в композиции.

8.8 Прочность сцепления (адгезия) стяжек на основе цементного вяжущего на отрыв с бетонным основанием в возрасте 28 сут должна быть не менее 0,6 МПа. Прочность сцепления затвердевшего раствора (бетона) с бетонным основанием через 7 сут должна составлять не менее 50 % проектной.

8.9 При сосредоточенных нагрузках на пол более 20 кН толщина стяжки по тепло- или звукоизоляционному слою должна устанавливаться расчетом на местное сжатие и продавливание по расчетной методике, изложенной в СП 52-101.

8.10 В местах сопряжения стяжек, выполненных по звукоизоляционным прокладкам или засыпкам, с другими конструкциями (стенами, перегородками, трубопроводами, проходящими через перекрытия, и т.п.) должны быть предусмотрены зазоры шириной 25 – 30 мм на всю толщину стяжки, заполняемые звукоизоляционным материалом.

8.11 В целях исключения мокрых процессов, ускорения производства работ, а также обеспечения нормируемого теплоусвоения пола следует применять сборные стяжки из гипсоволокнистых, древесно-стружечных и цементно-стружечных листов или фанеры.

8.12 Легкий бетон стяжек, выполняемых для обеспечения нормируемого теплоусвоения пола, должен быть класса не ниже В5, а поризованный цементно-песчаный раствор прочностью на сжатие – не менее 5 МПа.

8.13 Отклонения поверхности стяжки от горизонтальной плоскости (просветы между контрольной двухметровой рейкой и проверяемой поверхностью) не должны превышать для покрытий из штучных материалов по прослойке, мм:

• из цементно-песчаного раствора, ксилолита, поливинилацетатцементно — опилочного состава, а также для укладки оклеечной гидроизоляции — 4
• на основе синтетических смол и клеевых композиций на основе цемента, а также из линолеума, паркета, ламинированного паркета, рулонных материалов на основе синтетических во локон и полимерных наливных покрытий- 2

8.14 В помещениях, при эксплуатации которых возможны перепады температуры воздуха (положительная и отрицательная), в цементно-песчаной или бетонной стяжке необходимо предусматривать деформационные швы, которые должны совпадать с осями колонн, швами плитперекрытий, деформационными швами в подстилающем слое. Деформационные швы расшиваются полимерной эластичной композицией.

8.15 В стяжках обогреваемых полов необходимо предусматривать деформационные швы, нарезаемые в продольном и поперечном направлениях.Швы прорезаются на всю толщину стяжки и расшиваются полимерной эластичной композицией. Шаг деформационных швов должен быть не более 6 м.

90000 Kerbal Joint Reinforcement on SpaceDock 90001 90002 Tired of rockets collapsing when physics initializes, but it would be fine if physics did not start with a jerk? 90003 90002 Irritated launch clamps can twist your rocket apart when physics starts for no apparent reason? 90003 90002 Need more joint stiffness because you’re playing Real Solar System and the stock joints just do not cut it? 90003 90002 Then you need KERBAL JOINT REINFORCEMENT! 90003 90010 Shortened Features List 90011 90012 90013 Physics Easing 90014 90013 Launch Clamp Easing 90014 90013 Increase stiffness and strengths of connections 90014 90013 Stiffen interstage connections 90014 90013 Stiffen launch clamp connections 90014 90013 Option to make connections fail at lower forces to maintain difficulty in launching 90014 90025 90002 More information available on the forum page.90003 90028 90010 Version v3.3.3 90030 for Kerbal Space Program 1.3.0 90031 90011 90002 90030 Released on 2017-07-24 90031 90003 90002 v3.3.3 90038 Features 90038 —Recompile against KSP 1.3, ensure CompatChecker compatibility with 1.3 90003 90041 Download (37.87 KiB) 90003 90010 Version v3.3.2 90030 for Kerbal Space Program 1.2.2 90031 90011 90002 90030 Released on 2017-05-22 90031 90003 90051 90052 Bugfixes —Fix multijoints breaking IR joints and any other exempted parts from moving 90053 90054 90055 Download (37.61 KiB) 90003 90010 Version v3.3.1 90030 for Kerbal Space Program 1.2 90031 90011 90002 90030 Released on 2016-10-30 90031 90003 90002 v3.3.1 90038 Bugfixes 90038 —Fix a critical bug involving unphysical forces applied to vessels on load / unload of other vessels and SOI switches 90003 90069 Download (37.75 KiB) 90003 90010 Version v3.3.0 90030 for Kerbal Space Program 1.2 90031 90011 90002 90030 Released on 2016-10-27 90031 90003 90002 v3.3.0 90038 Features 90038 —Recompile to fix for KSP 1.2 90038 —Update method of handling multi-part-joints to ensure compatibility with Konstruction mod 90038 —Removal of old symmetry-based multi-part stabilization due to ineffectiveness in all situations to reduce overhead 90038 —Implementation of new vessel-part-tree leaf-based stabilization for greater stability on space stations and other convoluted shapes 90003 90086 Download (37.62 KiB) 90003 90010 Version v3.2.0 90030 for Kerbal Space Program 1.1.3 90031 90011 90002 90030 Released on 2016-06-30 90031 90003 90051 90052 Features —Recompile to ensure KSP 1.1.3 compatibility —Change multi-part-joint system to stabilize space stations and similar vehicles with very large masses connected by very flexy parts 90053 90054 90100 Download (38.26 KiB) 90003 90010 Version v3.1.7 90030 for Kerbal Space Program 1.1.2 90031 90011 90002 90030 Released on 2016-05-01 90031 90003 90051 90052 Features —Recompile to ensure KSP 1.1.2 compatibility, especially within CompatibilityChecker utility 90053 90054 90114 Download (37.03 KiB) 90003 90010 Version v3.1.6 90030 for Kerbal Space Program 1.1.1 90031 90011 90002 90030 Released on 2016-04-30 90031 90003 90051 90052 Features —Update to ensure KSP 1.1.1 compatibility —Minor optimization in joint setups —Remove B9 pWings from stiffening exemption, as it is unnecessary 90053 90054 90128 Download (36.99 KiB) 90003 90010 Version v3.1.5 90030 for Kerbal Space Program 1.1 90031 90011 90002 90030 Released on 2016-04-20 90031 90003 90002 v3.1.5 90038 Features 90038 —Updated to be compatible with KSP 1.1 90038 —Very minor efficiency improvements in physics easing and stiffening of joints 90038 —Fully exempt EVAs from all KJR effects 90038 —Update config parameters to function with stock fixing of never -breakable joints bug 90003 90145 Download (37.57 KiB) 90003 90010 Version v3.1.4 90030 for Kerbal Space Program 1.0.5 90031 90011 90002 90030 Released on 2016-02-18 90031 90003 90002 90156 No changelog provided 90157 90003 90159 Download (37.49 KiB) 90003 90010 Stats for Kerbal Joint Reinforcement 90011 90163 Downloads over time 90164 90163 New followers per day 90164 .90000 Selecting joint reinforcement — Construction Specifier 90001 90002 Photo courtesy Neumann / Smith Architecture 90003 90004 90005 by Dan Zechmeister, PE, FASTM, and Jeff Snyder, MBA 90006 90007 In a time of increasingly complex building enclosure systems, the masonry industry is striving to rediscover the simplistic principles that have made it a frequent material choice throughout history. One of these is the ‘less-is-more’ principle, which holds true when it comes to selecting wire reinforcement for reinforced masonry wall systems.90008 90004 Standard 9-gauge (MW11), ladder-shaped wire fabricated with butt-welded cross-rods spaced 406-mm (16-in.) On center (oc) better facilitates structurally required rebar placement, grout flow and consolidation, and shrinkage control for concrete masonry unit (CMU) walls. To understand why, it is important to know the history and rational behind horizontal joint reinforcement. 90008 90004 According to the National Concrete Masonry Association (NCMA) TEK 12-2B (2005), 90002 Joint Reinforcement for Concrete Masonry 90003, CMU joint reinforcement was «initially conceived primarily to control wall cracking associated with horizontal thermal or moisture shrinkage or expansion and as an alternative to masonry headers when tying masonry wythes together.»The TEK note goes on to state it» also increases a wall’s resistance to horizontal bending, but is not widely recognized by the model building codes for structural purposes. » 90008 90004 The most dramatic design change in single and multi-wythe masonry walls since wire reinforcement became the norm in the 1960s was the shift to vertical and horizontal steel reinforcement (rebar) in CMU in the 1990s. This encompassed all of North America’s unreinforced markets, not just seismic zones. 90008 90004 According to Table 2 in NCMA TEK 10-3 (2003), 90002 Control Joints for Concrete Masonry Walls? Alternative Engineered Method 90003 ( «Maximum Spacing of Horizontal Reinforcement to Meet the Criteria As> 0.0007 An «), for ungrouted or partially grouted walls, vertical spacing of wire is 406-mm (16-in.) Oc for 203- and 305-mm (8- and 12-in.) CMU block. Additionally, Table 2 states the 406-mm (16-in.) Spacing applies to 9-gauge (MW11) wire with two wires (one wire per face shell of the block). A CMU wall without frequently spaced vertical rebar (s) and corresponding bond beam (s) with rebar encapsulated in grout is rare. 90008 Ladder-shaped wire promotes code required rebar centering. 90002 Images courtesy John Maniatis 90003 Truss-shaped wire interferes with code-required rebar centering.90004 90008 90004 90005 Truss versus ladder 90007 90006 Horizontal joint reinforcement has evolved quite a bit over the decades. In the beginning, the truss shape was the norm for unreinforced masonry walls. As NCMA TEK 12-2B implies, the truss shape offered some resistance to wall spanning in the horizontal direction because of three wires-two longitudinal and one diagonal. However, since most masonry walls are now, typically, designed to span in the vertical direction, steel rebar and grout are placed vertically.90008 90004 90002 Rebar placement 90003 90006 When structural engineers design reinforced masonry, they typically call for the vertical bar to be placed in the center of block cells. In Articles 3.4 B.11.a & b, the 2013 Masonry Standard Joint Committee (MSJC) 90002 Building Code Requirements and Specification for 90003 90002 Masonry Structures, 90003 requires placement tolerance for vertical rebar to be ± 12.7 mm (½ in.) Across the width of the block, and ± 50.8 mm (2 in.) along the length of the block, measured from the center of the block cell.90008 90004 90002 Shape matters 90003 90006 Ladder-shaped wire has perpendicular cross-rods butt-welded at 406-mm (16-in.) Oc to the longitudinal wires. It is placed with cross-rods centered directly over the webs of the block (Figure 1). Placement of ladder wire in this manner eliminates obstructions caused by diagonal cross-rods common with the truss shape, especially where block cells are designed to contain vertical bars (Figure 2). 90008 90004 90002 Grout flow 90003 90006 Another advantage of ladder-shaped wire is evident when grout is placed and consolidated.The absence of diagonal (truss) cross-wires improves the flow and consolidation of grout. Under Articles 3.43 B.4.d, the 90002 MSJC Code 90003 typically requires CMU block (90002 i.e. 90003 hollow units) to be placed so vertical cells to be grouted are aligned. This provides an unobstructed path for grout flow. According to NCMA TEK 12-2B, «Because the diagonal cross wires may interfere with the placement of vertical reinforcing steel and grout, truss-type joint reinforcement should not be used in reinforced or grouted walls.»90008 90004 90054 90008 90004 90002 Shrinkage control 90003 90006 Ladder-shaped wire placed with cross-rods centered directly over block webs has yet another distinctive advantage. It positions butt-welded T-intersections of each longitudinal wire with cross-rods directly over T-intersections where block face shells meet each web. When laid in running bond pattern, two-cell block are placed with face shell mortar bedding only. Block webs are only mortar-bedded adjacent to vertically reinforced cells.90008 90004 Face-shell mortar bedding will extrude at the webs when compressed during block placement, completely encapsulating the wire T-intersections, bonding the wire to the concrete masonry (Figure 3). Hence, the net result should be improved shrinkage crack control. 90008 Ladder-shaped wire improves shrinkage control. Heavy-duty 4.8-mm (3/16-in.) Diameter wire leaves inadequate room for mortar coverage. 90004 90005 Standard 9-gauge versus heavy-duty 3/16 90007 90006 Besides its shape (90002 i.e. 90003 truss or ladder), wire thickness is important in the placement process. The most common mortar joint thickness specified is 9.5 mm (3/8 in.). The largest diameter of wire allowed by Section 6.1.2.3 of 90002 MSJC Code 90003 would be half the mortar joint thickness-4.8 mm (3/16 in.). There are compelling reasons why the use of 9-gauge wire (90002 ie 90003 3.8 mm [0.148 in.) Is more appropriate than a larger wire size that is heavy-duty (90002 ie 90003 4.8 mm [3/16 in.]) . 90008 90004 90002 Placement tolerances 90003 90006 The 90002 MSJC Code 90003 tolerance for the placement of the mortar bed joint thickness is ± 3.2 mm (1/8 in.), As clarified in Article 3.3 F. 1. b. Therefore, a specified mortar joint of 9.5 mm (3/8 in.) Would be allowed to vary from 12.7 to 6.4 mm (½ to ¼ in.) In thickness. With an as-built mortar joint thickness of ¼ to 3/8 inch, using heavy-duty 3/16-in. wire with hot-dip galvanized coating (per 90002 MSJC Code 90003 Section 6.1.4.2), would leave inadequate room for mortar cover to encapsulate the wire (Figure 4). Quite literally, block could be placed directly on the wire (90002 i.e.90003 block on wire on block). 90008 90004 In an article in the January тисяча дев’ятсот дев’яносто п’ять issue of 90002 Masonry Construction 90003 magazine, «Selecting the Right Joint Reinforcement for the Job,» author Mario J. Catani states: 90008 90004 One compelling reason to use 9-gauge reinforcement is for fit and constructability. While the code allows joint reinforcement to have a diameter one half the mortar joint width, the tolerances allowed for units, joints and the wire itself can hinder the placement of large diameter reinforcement.Use it only when there is no other choice. 90008 90004 90005 Forming corners 90007 90006 There is some debate regarding the merits of ordering factory prefabricated inside and outside corners versus field-forming them onsite. Since the 90002 MSJC Code 90003 does not distinguish the merits of either method (and, indeed, barely recognizes them), some interpretation is necessary. 90008 90004 The standard for lapping wire reinforcement at any location is always the same-it requires a 152 mm (6 in.) Minimum whether lapping straight 3.1-m (10-ft) sections one to another or where a straight section meets a corner (per Article 3.4 B.10.b). This requirement can also be applied to field-formed corners. The inside longitudinal wire can be cut and bent to form a 90-degree angle with a minimum of 152 mm (6 in.) Of lap paralleling the newly formed inside longitudinal wire (Figure 5). 90008 90004 Factory-prefabricated corners may seem like the natural choice, but this can require additional lead time and cost for any size or configuration other than standard (8- or 12-in.) Two-wire reinforcement. This is especially the case for custom-made adjustable hook and eye configurations. 90008 90004 Field-formed corners have many advantages. They meet all 90002 MSJC Code 90003 requirements and are easily formed to fit any corner condition. Each leg can be formed to fit to length, plus lapped in each direction off a corner, minimizing wasteful leftover from 3.1-m lengths that would otherwise head to a landfill. Field-formed corners eliminate lead time, cost less per lineal foot than factory-fabricated pieces, and only take a minute to cut and form to fit at the work station.90008 This shows a simple three-step sequence to field form corners. Code approved mesh ties are safe, economical, and readily available. 90002 Image courtesy Matt Fowler 90003 90004 90008 90004 90008 90004 90008 90004 90008 90004 90008 90004 90008 90004 90008 90004 90008 90004 90008 90004 90005 Intersecting walls 90007 90006 90002 MSJC Code 90003 allows prefabricated T-horizontal wire reinforcement sections where an interior non-loadbearing masonry wall intersects another for lateral support.However, this may not be the best selection. Such T-sections are typically embedded 406-mm (16-in.) On center during construction in the longitudinal wall, leaving the projecting leg of the T-section extending out approximately 609-mm (24 in.) Until the intersecting wall is constructed. 90008 90004 Many masons will agree the exposed wire sections can be dangerous onsite, especially at eye height. Fortunately, 90002 MSJC Code 90003 also allows 6.3-mm (1/4-in.) Mesh galvanized hardware cloth for interior non-loadbearing interesting walls (Figure 6).Additionally, 90002 MSJC Code 90003 allows Z-strap anchors for walls that intersect where shear transfer is desired. Projecting Z-straps share similar safety concerns with exposed T-sections. They only need to be used where the structural engineer indicates shear transfer. When applicable, mesh ties are typically the best choice. They are readily available, simple, and economical to install, and can be safely bent out of the way until the intersecting wall reaches their height. 90008 90004 90005 Finish options 90007 90006 The two most common finishes for wire reinforcement are mill galvanized and hot-dip galvanized.The first category is allowed by the 90002 MSJC Code 90003 for most interior applications not in contact with moisture or high humidity. These standard mill galvanized finishes are produced through electro-galvanization-a process where a layer of zinc is bonded to steel when a current of electricity is run through a saline / zinc solution with a zinc anode and steel conductor. This process is undertaken when wire is in its raw state, before fabrication (90002 i.e. 90003 cut and welded to shape) into wire reinforcement.90008 90004 This guide outlines joint reinforcement selection. 90002 Image courtesy Masonry Institute of Michigan 90003 Hot-dip galvanization is required for all exterior applications, as well as any interior walls exposed to moisture or high humidity. It is a process of coating steel with a heavy layer by immersing it in a bath of molten zinc. This process is undertaken after wire is fabricated to form reinforcement. 90008 90004 90005 Myriad advantages 90007 90006 Unfortunately, not all who design or specify wire reinforcement have kept pace with the shift to reinforced CMU.There are many pockets of the country where antiquated truss shape and / or heavy-duty wire are still in use. Figure 7 reviews the advantages and disadvantages of ladder and truss shapes, along with standard 9-gauge versus heavy-duty wire reinforcement. 90008 90004 Additionally, ladder-shaped wire with 9-gauge side- and cross-rods has other advantages including lower production, packaging, and shipping costs. Lighter bundle weight reduces risk of back injury when they are handled on the jobsite.Ladder configuration also streamlines wire, rebar, and grout installation-this, in turn, enhances bricklayer productivity. 90008 90004 90002 Specification 90003 90006 The following, and Figure 8, provides an example of the recommended wording for horizontal joint reinforcement in single and multi-wythe masonry walls: 90008 90004 PART 2 PRODUCTS 90006 2.1 Masonry Reinforcing 90006 A. Joint Reinforcement, General: ASTM A 961 90006 1. Interior Walls: Mill galvanized, ASTM A 641 (0.10 ounces per square foot), carbon steel.90006 2. Exterior Walls: Hot-dip galvanized, ASTM A 153 Class B-2 (1.50 ounces per square foot) carbon steel. 90006 3. Interior Walls Exposed to High Humidity: Hot dip galvanized, ASTM A 153 Class B-2 (1.50 ounces per square foot) carbon steel). 90006 4. Wire Size and Side Rods: W1.7 or 0.148 inch diameter (9 gage). 90006 5. Wire Size and Cross Rods: W1.7 or 0.148 inch diameter (9 gage). 90006 6. Wire Size for Veneer Ties: W2.8 or 0.1875 inch diameter (3/16 inch). 90006 7. Spacing for Cross Rods: 16 inches on center 90006 8.Provide in lengths of 10 feet. 90008 90178 90179 B. Masonry Joint Reinforcement for Single-Wythe Masonry: Ladder type with single pair of side rods. 90180 90179 C. Masonry Joint Reinforcement for Multi-Wythe Masonry: Ladder type with adjustable (two-piece) design, with separate double eye butt welded to side rod 16 inches on center. Double hook ties that engage eyes welded to reinforcement and resist movement perpendicular to wall. Hook tie length shall be sufficient to extend 1/2 inch minimum into outer face shell for hollow units and 1-1 / 2 inch minimum into solid units, but with a minimum 5/8 inch cover at outside face.90180 90183 90004 90008 Ladder-shaped wire, code required minimum lap, and butt-welded adjustable eye options are shown here. 90002 Image courtesy John Maniatis 90003 90004 90005 Conclusion 90007 90006 To control potential shrinkage cracking in a concrete masonry wall, it requires proper placement of control joints (CJs), along with placement of horizontal joint reinforcement. Horizontal joint reinforcement in a CMU wall does not prevent cracking, but controls it. Without it in a concrete masonry wall, shrinkage cracks may be visible and of a size penetrable by Mother Nature.90008 90004 With 9-gauge ladder-shaped joint reinforcement in a concrete masonry wall, the longitudinal wire will go into tension as the concrete masonry is shrinking. Hence, an occasional microscopic crack should not be noticeable and would be less vulnerable to the elements. Use of truss-shaped wire does not meet code compliance and may negatively impact the integrity of a reinforced concrete masonry wall. 90008 90004 When it comes to masonry wire reinforcement, the old adage ‘less is more’ could not be any more true.Ladder-shaped wire, fabricated in 3.1-m (10-ft) long pieces with 9-gauge continuous side-rods and butt-welded 9-gauge cross-rods spaced 406-mm (16-in.) Oc is the ideal choice for high-performance, economically designed CMU wall systems. 90008 90004 90002 Dan Zechmeister, PE, FASTM, has been the executive director and structural services director of the Masonry Institute of Michigan (MIM) since 1986. He is an active member of ASTM, and a 2012 recipient of its International Award of Merit. Zechmeister also serves as a board member of the American Institute of Architects (AIA) Building Enclosure Council of Greater Detroit.He can be contacted at [email protected]. 90003 90008 90004 90002 Jeff Snyder, MBA, is the president of Masonpro Inc., a provider of specialty accessories to unit mason contractors. He has extensive field experience, including project managing for mason contractors in Texas and New Mexico. Snyder is a trustee with MIM, serving on its Generic Wall Design Committee. He can be contacted at [email protected]. 90003 90008 .90000 Less Is More — Masonry Magazine 90001 90002 Joint Reinforcements 90003 90002 Mason contractors are empowered to help improve joint reinforcement specifications. 90003 90006 By Dan Zechmeister, PE, FASTM and Jeff Snyder, MBA 90007 90008 Do you still encounter project specifications that require (often or occasionally) truss-shaped wire, heavy-duty wire, prefabricated corners and / or Ts? If so, it’s time to climb the ladder, so your company can positively impact the constructability, performance and cost effectiveness of your client’s projects.90009 90008 Far too many specifications for horizontal joint reinforcement inadvertently include requirements that could undermine the capacity to meet code and negatively impact the constructability, performance and cost effectiveness of reinforced CMU wall systems. Some requirements are simply an unnecessary waste, while a few, like prefabricated Ts for intersecting walls, may even elevate safety concerns. 90009 90008 Mason contractors can empower themselves to intervene (prior to or during the submittal process) to educate the project designers and construction professionals with myriad code compliance and performance data available.There should be receptive ears, because no one wants to take responsibility for requiring you to proceed with an installation linked to specifications that could undermine your capacity to meet the code. 90009 90008 Another benefit of this exercise is, when successful, you will not only positively impact the particular project at hand with updating the designer’s master specifications, but will have a domino effect on future projects. 90009 90008 The main objective of this article is to provide you with tools (knowledge) that support the premise «less is more,» when it comes to using horizontal joint reinforcement.We begin with a brief history including why, where and what wire is, including many factors that impact its use. We also touch on corners, intersections and finishes. Finally, we present a generic specification that provides IBC and TMS Code compliance with an eye on improved constructability and economy. 90009 90018 History 90019 90008 According to the National Concrete Masonry Association (NCMA) TEK 12-2B (2005) Joint Reinforcement for Concrete Masonry: «It was initially conceived primarily to control wall cracking associated with horizontal thermal or moisture shrinkage or expansion and as an alternative to masonry headers when tying masonry wythes together.»90009 90008 This TEK Note goes on to state that it «… also increases a wall’s resistance to horizontal bending, but is not widely recognized by the model building codes for structural purposes.» 90009 90008 The most dramatic design change in single- and multi-wythe masonry walls, since wire reinforcement became the norm in the 1960s, was the shift to vertical and horizontal steel reinforcement (rebar) in CMU (block) in the 1990s. This encompassed all of North America’s unreinforced markets, not just seismic zones.90009 90008 According to NCMA TEK 10-3 (2003), Table 2 (Maximum Spacing of Horizontal Reinforcement to Meet the Criteria As> 0.0007 An) for un-grouted or partially grouted walls vertical spacing of wire is 16 inches on center for eight- and 12-inch block. Additionally, Table 2 states the 16-inch spacing applies to nine-gauge wire with two wires (one wire per face shell of the block). Rare is a CMU wall without frequently spaced vertical rebar and corresponding bond beam (s) with rebar encapsulated in grout.90009 90018 Truss shape versus ladder shape 90019 90008 When it comes to using horizontal joint reinforcement, it’s no longer your father’s Buick. In the beginning, truss was the norm for unreinforced masonry walls. As the NCMA TEK 12-2B implies, the truss shape is stiffer in the plane of the wall than the ladder shape, because of three wires (two longitudinal and one diagonal). However, most masonry walls are designed today to span in the vertical direction, hence, steel rebar and grout are placed vertically.90009 90018 Rebar placement 90019 90008 When structural engineers design reinforced masonry, they typically call for the vertical bar to be placed in the center of block cells. The masonry code requires placement tolerance for vertical rebar to be +/- ½ inch (across the width of the block) and +/- two inches (along the length of the block) measured from the center of the block cell (Masonry Standards Joint Committee, The Masonry Society (TMS) 2011 Specification: Articles 3.4 B. 11. a & b).90009 90036 90037 90038 90039 90040 90008 Figure 1. Ladder-shaped wire promotes code-required rebar centering, and does not get in the way of grout placement. 90009 90043 90044 90038 90039 90040 90008 Figure 2. Truss-shaped wire interferes with code-required rebar centering, and may cause grout to hang up on the diagonal wires. 90009 90043 90044 90052 90053 90018 Shape matters 90019 90008 Ladder-shaped wire has perpendicular cross-rods butt welded at 16 inches on center to the longitudinal wires.It’s placed with cross-rods centered directly over the webs of the block (see Figure 1). Placement of ladder wire in this manner eliminates obstructions caused by diagonal cross-rods common with the truss shape, especially where block cells are designed to contain vertical bars (see Figure 2). 90009 90018 Grout flow 90019 90008 Another advantage of ladder wire is evident when grout is placed and consolidated. The absence of diagonal (truss) cross wires improves the flow and consolidation of grout.Typically, the masonry code requires block (hollow units) to be placed so vertical cells to be grouted are aligned, which provides an unobstructed path for grout flow (TMS 2011 Specification: Article 3.3 B. 3. D). According to NCMA TEK 12-2B, «… .because the diagonal cross wires may interfere with the placement of vertical reinforcing steel and grout, truss-type joint reinforcement should not be used in reinforced or grouted walls.» 90009 Figure 3. Ladder-shaped wire improves shrinkage control by forming interlocking Ts at cross webs.90018 Shrinkage control 90019 90008 Ladder wire placed with cross rods centered directly over block webs has yet another distinctive advantage. It positions butt welded «T» intersections of each longitudinal wire with cross rods directly over «T» intersections, where block face shells meet each web. When laid in running bond pattern, two-cell block are placed with face shell (exterior and interior) mortar bedding only. Block webs are only mortar bedded adjacent to vertically reinforced cells.Face shell mortar bedding will extrude at the webs when compressed during block placement, completely encapsulating the wire «T» intersections, bonding the wire to the concrete masonry (see Figure 3). Hence, the net result should be improved shrinkage crack control. 90009 90018 Standard nine-gauge vs heavy-duty 3/16-inch 90019 90008 Besides its shape (truss or ladder), wire thickness is important in the placement process. The most common mortar joint thickness specified is 3/8 inch. The maximum wire diameter allowed by the masonry code would be one-half of the 3/8-inch mortar joint thickness, or 3/16 inch [TMS 2011 Code: Section 1.16.2.3]. However, there are compelling reasons to use the smaller size nine-gauge wire. 90009 Figure 4. Heavy-duty, 3/16-inch-diameter wire can leave inadequate room for proper mortar coverage. Both the top and bottom of wire could be in direct contact with masonry unit (no mortar coverage). 90018 Placement tolerances 90019 90008 The masonry code tolerance for the placement of the mortar bed joint thickness is +/- 1/8 inch [TMS 2011 Specification: Article 3.3 F. 1. b.]. Therefore, a specified mortar joint of 3/8 inch would be allowed to vary from ½ to ¼ inch in thickness.With an as-built mortar joint thickness of ¼ to 3/8 inch, using heavy-duty 3/16-inch wire with hot dip galvanized coating [TMS 2011 Code: Section 1.16.4.2] could leave inadequate room for mortar cover encapsulation ( see Figure 4) when considering the galvanized coating, the levelness of the top surface of the CMUs supporting the wire and the planeness of the wire. 90009 90008 Quite literally, block could be placed directly on the wire (block on wire on block). According to an article by Mario J.Catani in the January тисяча дев’ятсот дев’яносто п’ять Masonry Construction magazine entitled, «Selecting the Right Joint Reinforcement for the Job,» he states, «One compelling reason to use nine-gauge reinforcement is for fit and constructability. While the code allows joint reinforcement to have a diameter one half the mortar joint width, the tolerances allowed for units, joints and the wire itself can hinder the placement of large diameter reinforcement. Use it only when there is no other choice. » 90009 Figure 5. A simple, three-step sequence to field form corners 90018 Forming corners 90019 90008 There is some debate regarding the merits of ordering factory prefabricated inside and outside corners versus field-forming them.Since the TMS Code does not distinguish the merits of either method (and, indeed, barely recognizes them), some commentary is warranted. The industry standard for lapping wire reinforcement at any location is always the same: It requires at least six inches, whether lapping straight 10-foot sections one to another, or where a straight section meets a corner (TMS 2011 Specification: Article 3.4 B. 10.b). This requirement also can be applied to field-formed corners. The inside longitudinal wire can be cut and bent to form a 90-degree angle with a minimum of six inches of lap paralleling the newly formed inside longitudinal wire (see Figure 5).90009 90008 Factory-prefabricated corners may seem like the natural choice, but this can require additional lead time and cost for any size or configuration other than standard eight- or 12-inch, two-wire reinforcement. This is especially the case for custom-made adjustable hook-and-eye configurations. 90009 Figure 6. Code-approved mesh ties are safe, economical and readily available. 90018 Intersecting walls 90019 90008 TMS Code allows prefabricated T-horizontal wire reinforcement sections, where an interior non-loadbearing masonry wall intersects another for lateral support.However, this may not be the best selection. Such T-sections are typically embedded 16 inches on center during construction in the longitudinal wall, leaving the projecting leg of the T-section extending out about 24 inches until the intersecting wall is constructed. 90009 90008 Many masons will agree the exposed wire sections can be dangerous onsite, especially at eye height. Fortunately, the TMS Code also allows ¼-inch mesh galvanized hardware cloth for interior non-loadbearing interesting walls (see Figure 6).Additionally, the TMS Code requires Z-strap anchors for walls that intersect where shear transfer is desired. Projecting Z-straps pose similar safety concerns with exposed T-sections. 90009 90008 However, they only need to be used when the design requires shear transfer, which is often misunderstood by the design community. When applicable, mesh ties are typically the best choice. They are readily available, simple, and economical to install, and can be safely bent out of the way until the intersecting wall reaches their height.90009 90008 For intersecting interior loadbearing walls, lateral support is usually achieved from supporting framing members, and is not dependent on intersecting walls for lateral support. 90009 90018 Finish options 90019 90008 The two most common finishes for wire reinforcement are mill galvanized and hot-dip galvanized. The first category is allowed by the TMS Code for most interior applications not in contact with moisture or high humidity. Standard mill galvanized finishes are produced through electro-galvanization, a process where a layer of zinc is bonded to steel when a current of electricity is run through a saline / zinc solution with a zinc anode and steel conductor.This process is undertaken when wire is in its raw state, before fabrication (i.e. cut and welded to shape) into wire reinforcement. 90009 90008 Hot-dip galvanization is required for all exterior applications, as well as any interior walls exposed to moisture or high humidity. It is a process of coating steel with a heavy layer by immersing it in a bath of molten zinc. This process is undertaken after wire is fabricated to form reinforcement. 90009 90008 In a few unique applications, stainless steel might provide value.Though very expensive, it may be necessary in high-corrosive environments or where non-magnetic requirements are necessary. 90009 Figure 7. This guide outlines joint reinforcement selection. 90018 Myriad advantages 90019 90008 Unfortunately, not all who design or specify wire reinforcement have kept pace with the shift to reinforced CMU. There are many pockets of the country where antiquated truss shape and / or heavy-duty wire are still in use. Figure 7 reviews the advantages of ladder and disadvantages of truss, along with standard nine-gauge versus heavy-duty wire reinforcement.90009 90008 Additionally, ladder-shaped wire with nine-gauge side- and cross-rods has other advantages including lower production, packaging and shipping costs. Lighter bundle weight reduces risk of back injury when they are handled on the jobsite. Ladder configuration also streamlines wire, rebar and grout installation. This, in turn, enhances bricklayer productivity. 90009 Figure 8. Ladder-shaped wire, code-required minimum lap, and butt-welded adjustable eye options are shown here. 90018 Generic specifications 90019 90008 The following, and Figure 8, provide an example of the recommended wording for horizontal joint reinforcement in single- and multi-wythe masonry walls: 90009 90006 Part 2 products 90007 90008 90113 2.1 Masonry Reinforcing 90114 90115 90113 A. Joint Reinforcement, General: ASTM A 961 90114 90009 90119 90120 Interior Walls: Mill galvanized, ASTM A 641 (0.10 ounces per square foot), carbon steel 90121 90120 Exterior Walls: Hot-dip galvanized, ASTM A 153 Class B-2 (1.50 ounces per square foot) carbon steel 90121 90120 Interior Walls Exposed to High Humidity: Hot-dip galvanized, ASTM A 153 90115 Class B-2 (1.50 ounces per square foot) carbon steel 90121 90120 Wire Size and Side Rods: W1.7 or 0.148-inch-diameter (nine-gauge) 90121 90120 Wire Size and Cross Rods: W1.7 or 0.148-inch-diameter (nine-gauge) 90121 90120 Wire Size for Veneer Ties: W2.8 or 0.1875-inch-diameter (3/16 inch) 90121 90120 Spacing for Cross Rods: 16 inches on center 90121 90120 Provide in lengths of 10 feet 90121 90137 90008 90113 B. Masonry Joint Reinforcement for Single-Wythe Masonry: Ladder type with single pair of side rods 90114 90009 90008 90113 C. Masonry Joint Reinforcement for Multi-Wythe Masonry: Ladder type with adjustable (two-piece) design, with separate double-eye butt welded to side rods 16 inches on center; double hook ties that engage eyes welded to reinforcement and resist movement perpendicular to wall.Hook tie length shall be sufficient to extend 1/2-inch minimum into outer face shell for hollow units and 1.5-inch minimum into solid units, but with a minimum 90114 90115 90113 5/8-inch cover at outside face. 90114 90009 90018 Conclusion 90019 90008 Mason contractors can positively impact the constructability, performance and cost effectiveness of their projects, all with the added benefit of upgrading the designer’s specifications to better meet code requirements. 90009 90008 To control potential shrinkage cracking in a concrete masonry wall, it requires proper placement of the control joints and horizontal joint reinforcement.Horizontal joint reinforcement in a CMU wall does not prevent cracking, but, rather, controls it. Without it in a concrete masonry wall, shrinkage cracks may be visible and of a size more easily penetrable by Mother Nature. 90009 90008 With nine-gauge, ladder-shaped joint reinforcement in a concrete masonry wall, the longitudinal wire goes into tension as the concrete masonry is shrinking. Hence, an occasional microscopic crack should not be noticeable and would be less vulnerable to the elements.Use of truss-shaped wire that must be altered to fit around vertical reinforcing may not meet code compliance and may negatively impact the integrity of a reinforced concrete masonry wall system. 90009 90008 In summary, with respect to the statement «could undermine the capacity to meet code,» consider the following: Ladder wire, when placed correctly, will not interfere with the minimum code requirement for placement tolerances of the vertical bar. Ladder wire, when placed correctly, will not interfere with meeting the minimum code requirements for placing and consolidating grout.Standard nine-gauge wire would leave more room for mortar cover encapsulation, when the mortar bed joint thickness is constructed within the minimum code tolerances. 90009 90008 When it comes to masonry wire reinforcement, the old adage «less is more» holds true. Ladder wire, fabricated in 10-foot lengths with nine-gauge continuous side rods and butt welded nine-gauge cross-rods spaced 16 inches on center is the ideal for high-performance CMU wall systems. 90009 90008 Field-formed corners and mesh ties at intersections offer greater performance, economy and safety.Meet code and performance requirements with standard mill galvanized for interior and hot-dip galvanized for exterior and high-moisture or humid environments. 90009 90163 90008 90165 90113 Dan Zechmeister 90114, PE, AIA Detroit Honorary Affiliate, FASTM, has been executive director and structural services director of the Masonry Institute of Michigan (MIM) since 1990. MIM provides detailing and technical assistance to the architectural and engineering community in Michigan and Northwest Ohio.Zechmeister is an active member of ASTM. He can be contacted at [email protected]. 90168 90009 90008 90165 90113 Jeff Snyder 90114 has been president of MASONPRO Inc. since 1988. MASONPRO provides specialty accessories to unit mason contractors in the U.S. and Canada. His masonry field experience includes project managing for mason contractors in Texas and New Mexico. Snyder is a trustee with the Masonry Institute of Michigan and serves on their Generic Wall Design Committee. He can be contacted at jeff @ masonpro.com. 90168 90009 .90000 Kerbal Space Program — Realism Overhaul · GitHub 90001 Skip to content KSP-RO Sign up 90002 90003 Why GitHub? 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