Este trabalho apresenta uma análise teórica e experimental do desempenho de vigas de concreto armado com telas soldadas com relação à resistência, à força cortante e ao controle da fissuração. O programa experimental englobou cinco séries de vigas com variação dos seguintes parâmetros: largura e altura das vigas, taxa de armadura transversal, taxa de armadura lateral e tipo de ancoragem dos fios verticais da tela no bordo comprimido da viga. Os modelos experimentais foram constituídos por doze vigas VQ (15 x 40 x 305), relação a/d= 2,78 e sete vigas VS (20 x 70 x 540), a/d= 2,66, ambas com seção T (bf = 50 cm e hf = 10 cm). O esquema de ensaio foi de uma viga simplesmente apoiada, com duas forças concentradas aplicadas. A formulação proposta, elaborada com base na teoria do cisalhamento-atrito, considerando a contribuição da armadura lateral na resistência à força cortante, foi analisada mediante os resultados obtidos nos ensaios. Analisaram-se também as aberturas das fissuras de cisalhamento na alma. A contribuição da armadura lateral da tela soldada deve-se à alteração em dois mecanismos resistentes alternativos: aumento da parcela de engrenamento dos agregados afetada pelas menores aberturas das fissuras de cisalhamento na alma e pelo efeito de pino dos fios da armadura lateral nos pontos em que são interceptados pelas fissuras diagonais. De modo geral, as vigas armadas com telas soldadas apresentaram menores aberturas de fissuras de cisalhamento na alma, um panorama de fissuração mais sistemático e maior reserva de resistência nas proximidades do colapso. / This work presents a theoretical-experimental analysis of performance shear design and cracking control in reinforced concrete beams with welded wire mesh. The experimental program consisted of five series of beams with variation of the following parameters: width and depth of the beam, transversal reinforcement ratio, lateral reinforcement ratio and type of stirrup anchorage in beam compression zone. The tested specimens comprised of twelve beams VQ (15 x 40 x 305), shear span-to-depth a/d= 2,78 and seven beams VS (20 x 70 x 540), a/d= 2,66, both with T transversal section (bf = 50 cm e hf = 10 cm). The test setup was a simply supported beam, with two concentrated forces applied. The proposed model was based on shear friction, which took account of the lateral reinforcement contribution on shear design. This model was compared with the test results. It was also studied the shear crack widths on the web beam. The lateral reinforcement contribution is provided by two alternative strength mechanisms: the increasing of portion agreggate interlock affected by smaller diagonal crack widths and the dowel effect of lateral reinforcement wires intercepted by diagonal plane failure. Generally, the welded wire fabric beams presented smaller inclined shear cracks, a better cracking configuration and higher strength reserve close to colapse.

Este trabalho apresenta uma análise teórica e experimental do desempenho de vigas de concreto armado com telas soldadas com relação à resistência, à força cortante e ao controle da fissuração. O programa experimental englobou cinco séries de vigas com variação dos seguintes parâmetros: largura e altura das vigas, taxa de armadura transversal, taxa de armadura lateral e tipo de ancoragem dos fios verticais da tela no bordo comprimido da viga. Os modelos experimentais foram constituídos por doze vigas VQ (15 x 40 x 305), relação a/d= 2,78 e sete vigas VS (20 x 70 x 540), a/d= 2,66, ambas com seção T (bf = 50 cm e hf = 10 cm). O esquema de ensaio foi de uma viga simplesmente apoiada, com duas forças concentradas aplicadas. A formulação proposta, elaborada com base na teoria do cisalhamento-atrito, considerando a contribuição da armadura lateral na resistência à força cortante, foi analisada mediante os resultados obtidos nos ensaios. Analisaram-se também as aberturas das fissuras de cisalhamento na alma. A contribuição da armadura lateral da tela soldada deve-se à alteração em dois mecanismos resistentes alternativos: aumento da parcela de engrenamento dos agregados afetada pelas menores aberturas das fissuras de cisalhamento na alma e pelo efeito de pino dos fios da armadura lateral nos pontos em que são interceptados pelas fissuras diagonais. De modo geral, as vigas armadas com telas soldadas apresentaram menores aberturas de fissuras de cisalhamento na alma, um panorama de fissuração mais sistemático e maior reserva de resistência nas proximidades do colapso. / This work presents a theoretical-experimental analysis of performance shear design and cracking control in reinforced concrete beams with welded wire mesh. The experimental program consisted of five series of beams with variation of the following parameters: width and depth of the beam, transversal reinforcement ratio, lateral reinforcement ratio and type of stirrup anchorage in beam compression zone. The tested specimens comprised of twelve beams VQ (15 x 40 x 305), shear span-to-depth a/d= 2,78 and seven beams VS (20 x 70 x 540), a/d= 2,66, both with T transversal section (bf = 50 cm e hf = 10 cm). The test setup was a simply supported beam, with two concentrated forces applied. The proposed model was based on shear friction, which took account of the lateral reinforcement contribution on shear design. This model was compared with the test results. It was also studied the shear crack widths on the web beam. The lateral reinforcement contribution is provided by two alternative strength mechanisms: the increasing of portion agreggate interlock affected by smaller diagonal crack widths and the dowel effect of lateral reinforcement wires intercepted by diagonal plane failure. Generally, the welded wire fabric beams presented smaller inclined shear cracks, a better cracking configuration and higher strength reserve close to colapse.

Reinforced concrete shear walls as seismic force resisting systems may experience inelastic deformations if subjected to strong seismic excitations. These walls are designed to provide strength, stiffness, energy dissipation capacity and lateral drift control for seismic resistance. Shear wall deformability is largely dependent on adequate confinement of core concrete in boundary elements, prevention of longitudinal bar buckling, as well as proper design and detailing of the web section. Conventional transverse reinforcement placed in shear wall boundary elements consists of hoops, overlapping hoops and crossties, based on the geometry and number of longitudinal bars used. The confinement steel requirement of current building codes (ACI 318 or CSA A23.3) often results in congestion of steel cage due to the high transverse reinforcement ratio required. Placing multiple hoops with 135-degree bends combined with crossties to satisfy the code confinement requirements can create concrete placement and construction problems. In addition, the required time to assemble conventional steel cages with multiple individual ties per spacing can be time consuming, potentially impacting the overall cost and duration of construction. Welded Wire Reinforcement (WWR) is available in the construction industry as concrete reinforcement in the form of welded wire fabric (WWF) manufactured from relatively small diameter wires in comparison to the bar sizes typically used in structural applications. As an alternative to using conventional transverse hoops, prefabricated WWR grids can be used to provide required transverse reinforcement in boundary elements. WWR grids are manufactured using robots to weld cut steel pieces accurately before they are shipped to the job site, resulting in better construction quality and reduced construction time. However, research on the use of WWR is limited in the literature. Further experimental and analytical research is needed to establish design requirements for such reinforcement, especially when used in earthquake resistant construction with requirements for ductile response. The current research project, involved three main phases; i) tests of 3 large-scale reinforced concrete shear walls with WWR grids used as boundary element transverse reinforcement, ii) material tests of grid samples, including those cast in concrete, iii) non-linear finite element analysis. The wall tests were conducted under slowly-applied lateral deformation reversals to investigate their strength and ductility for suitability as seismic resistant structural elements. Material tests were conducted to have a better understanding of WWR behavior, especially their weld capacity. Analytical research was undertaken to expand the experimental findings on shear wall behavior, as well as to conduct parametric investigation to understand the impact of changes in grid strength and ductility. The results indicated that WWR grids can be used as boundary element transverse reinforcement in earthquake resistant shear wall. However, strength and ductility of grids should be established carefully prior to such application. Design strength of WWR grids should be established through burst tests to ensure ductile yielding of wire reinforcement prior to premature weld failure. Those grids that exhibit weld failures may be used with reduced design strength to permit the development of sufficient inelastic deformability in flexure-dominant shear walls.

The purpose of this research is to evaluate and compare the structural performance of composite floor slabs reinforced with 6 x 6 W1.4/W1.4 welded wire fabric (WWF) and STRUX 90/40 synthetic macro fibers. Slabs were subjected to flexural strength tests and concentrated load tests while monitoring load, steel deck strains, and deflections. Test results obtained from this test program were also compared to results from a similar test program conducted in 2001. Tests were also performed to obtain the average residual-strength of the fiber-reinforced concrete using the ASTM C 1399 (2003) standard test. All slabs were loaded until a complete failure was observed. The observed failure loads were compared to failure loads calculated by design guides published by the American Society of Civil Engineers (ASCE) and the Steel Deck Institute (SDI). The flexural strength tests showed that composite slabs reinforced with synthetic macro fibers and WWF exhibited strength and behavior that was almost identical. The observed values of strength were also within the range that was predicted by ASCE prediction models. At a typical office design load of 70 psf, all slabs exhibited midspan deflections that were much smaller than those necessary for serviceability requirements. The concentrated load tests also showed that the observed strength of all composite slabs tested was above those values predicted by ASCE and SDI models. However, an effective comparison between the WWF-reinforced and synthetic macro fiber-reinforced slab was difficult due to a poor shear bond in the latter slab prior to testing. The results of the ASTM C 1399 test verified the ability of concrete reinforced with synthetic macro fibers to meet average residual-strength values recommended by the SDI. / Master of Science