An experimental study has been conducted to study the cyclic behavior of reinforced concrete beams in which steel fibers were added to the concrete mix. Seven similar geometrically specimens in full scale were studied under four-point bending test in the form of slow cyclic loading. One sample as a control specimen was made without steel fibers or 0% volume fraction (vf) and six other samples with 1, 2 and 4% vf of steel fibers in twin models. The maximum and ultimate resistance, ductility, degradation of loading and unloading stiffness, absorption and dissipation of energy and equivalent viscous damping were studied in this investigation and the effect of steel fibers on the cyclic behavior was compared with each other. Generally, the addition of steel fibers up to a certain limit value (vf = 2%) improves the cyclic behavior of reinforced concrete beams and results in the increase of maximum strength and ultimate displacement.

As construction projects are becoming more deployed and more complicated at the same time, having an instrument for anticipation of success has become a primary requirement for every stakeholder. On this basis, several models have been introduced which implement different methods for anticipation of the entire goals or a series of goals of projects. In this research, at the first step, 16 criteria as instruments of anticipation of success and 33 factors as required instruments for obtaining success were extracted through library studies, semi-structured interviews and the Delphi method. At the next step, by having 169 questionnaires filled by senior managers of construction projects, the importance and priority of each of these 16 criteria and 33 factors for the initial phases of projects were determined according to Iran's local conditions. Ultimately, through modeling of data by a propagation neural network including 35 hidden layers, the anticipator model for success of construction projects during their initial phases was developed with Performance and Regression. This model is able to anticipate the level of realization of projects' success criteria according to the level of realization of success factors at the initial phase.

Steel bracings are one of the most widely used systems for resisting transverse loads in the design and retrofit of concrete and steel structures. This paper reports on an experimental and numerical study of the effects of core steel and the distance of the core from the casing on the behaviour of buckling-restrained braces. Laboratory models of six braces with a core made from conventional ST37 steel or ST37-n steel (softened at a temperature of 1000° using the O'Neill method) with a core–casing distance of 0, 2 or 3 mm were designed. The experimental results showed that, compared with the brace made from ST37 steel, the use of ST37-n steel resulted in a reduction of 32% in the tensile and compressive strengths of the brace. An increase in the core–casing distance in the ST37 and ST37-n braces resulted in reductions in the brace bearing capacity and energy dissipation by 26% and 52%, respectively. An increase in the core–casing distance to more than 2 mm resulted in loss of symmetry and stability of the hysteresis behaviour of the brace; in addition, distortion due to brace local buckling under pressure also intensified.

Following the adequate seismic behavior, the steel plate shear walls have gained popularity among the designers worldwide, and many buildings have been designed employing such walls as their lateral load-carrying system. Despite the fact that the steel shear walls using unstiffened thin plates outnumber the ones benefitting from stiffeners, it should be kept in mind that application of stiffeners prevents the buckling induced by lateral loads such earthquake or wind. On the other hand, the stiffeners enhance the stiffness and shear strength of the plate. Accordingly, this paper deals with an analytical and numerical investigation into the steel plates stiffened by unequaled vertical and horizontal stiffeners. The results obtained for the analyses led to the development of the analytical relations to compute the shear strength, stiffness, and displacement. To validate the proposed relations, analytical outputs were compared with those obtained from the numerical investigation indicating great accuracy of the proposed analytical relations. Moreover, in this paper, the design process of the stiffened steel plate shear walls has been presented based on the interaction between the plate and frame. The results indicate the addition of stiffeners to the steel plate, improves its shear strength by 6 to 15%. K E Y W O R D Sanalytical relations, displacement, shear stiffness, stiffened steel plate, strength, unequal subpanels