The shear behavior of six wide beams was was studied to investigate the effectiveness of various types of shear reinforcement in improving the shear capacity of wide beams. One specimen each was provided: without vertical stirrups, with vertical stirrups, independent bent-up bars, independent middepth horizontal bars, and the combination of vertical stirrups and bent-up bars. To study the effectiveness of longitudinal flexural reinforcement on the shear capacity of wide beams, an additional specimen without stirrups, but including approximately two-thirds of longitudinal flexural reinforcement that were arranged in column band, was investigated. The performances were measured in terms of deflection, crack patterns, concrete and steel strains, ultimate load, and modes of failure. The results showed that independent bent-up bars increased the shear capacity and ductility of wide beams. It was revealed that, although independent horizontal bars increased the shear capacity to some extent, the beam was less ductile through failure. The results also indicated that the beam with banded main reinforcement achieved larger failure load.

SUMMARY Industrialized building system (IBS) is a construction process that uses techniques, products, components or building systems that involve prefabricated components and on‐site installation. The structural behaviour of a prefabricated frame structure is widely affected by the specifications of the beam‐to‐column connection. The understanding on the real behaviour of a connection can be assessed by conducting full‐scale experimental tests. In this study, a new IBS hybrid steel–concrete connection in a full‐scale H‐subframe under monotonic loading is investigated. This innovative connection system, consists of precast concrete beam‐and‐column elements with embedded steel end connectors, is patented as Smart IBS. This paper reports the testing procedures and results of this semi‐rigid IBS beam‐to‐column connection to obtain the important attributes of the connection as well as its comparison with monolithic cast‐in‐place reinforced concrete model. The height of both H‐subframes is 3.3 m while the free length of the beam is 3.2 m. The incremental loads were applied as two point loads in one‐third and two‐third of the beam length. The characteristic relationships of the connection such as load to mid‐span deflection, strength, stiffness, ductility, failure modes and crack patterns are studied and compared between both structural systems. Copyright © 2012 John Wiley & Sons, Ltd.

Tubular structures are extensively recognized as a high efficiency and economically reasonable structural system for the design and construction of skyscrapers. The periphery of the building plan in a tubular system consists of closely spaced columns connected by circumferential deep spandrels. When a cantilever tube is subjected to a lateral load, it is expected that the axial stress in each column located in the flange frame of the tube is the same, but because of the flexibility of peripheral beams, the axial stress in the corner columns and middle columns is distributed unequally. This anomaly is called “shear lag”, and it is a leading cause of the reduction in efficiency of the structure. In this paper, the possible relation between shear lag and the type of lateral load subjected to these systems is investigated. The above relation is not yet considered in previous literatures. Three various plan shapes including rectangular, triangular and hexagon were modeled, analyzed, designed and subjected to the earthquake and wind load, separately. Further work is carried out to compare the shear lag factor of these structures with distinct plan shapes against different types of lateral load. It is observed that all types of structures with various plan geometry subjected to the wind load had a greater amount of shear lag factor in comparison with structures subjected to the static and dynamic earthquake loads. In addition, shear lag in structures with the hexagon shaped plan was at the minimum.

Reinforced concrete short corbels are widely used in engineering structures, such as bridges and precast structures. Therefore, the present comparative study was conducted on the structural behavior of the reinforced concrete corbels strengthened with carbon fiber-reinforced polymer (CFRP) laminates. For this purpose, numerical analysis was done using the finite element method. Therefore, nine models consisting of eight corbels strengthened with different CFRP arrangements in addition to an unstrengthened model were studied. The maximum load capacity, stiffness, ductility, and amount of absorbed energy were compared. In one of the above structure models, an innovative hunch was added at the top side of the corbel to column connection to investigate the differences with ordinary types of connections. Results revealed that the model used three bonded CFRP laminates all around the column and outside edges showed an 81% increase in loading capacity. Moreover, the corbel equipped with hunches had an 8% increase in stiffness compared to an ordinary corbel.