Tower cranes, on today’s typical building construction sites, are the centerpiece of production, hoisting and transporting of a variety of loads. Due to a simple crane limited capacity; there is an urgent need to use high capacity cranes such as tower cranes. However, we have to select an appropriate type of cranes to be utilized to reduce the associated coste as much as possible. In this research, we propose a method to select the suitable type of crane and locate the best place for crane erection based on a minimum radius for requested crane and minimum cost. To fulfill the target, a computer program is designed to numerate these problems, demonstrating an example explaining how to apply the program and the results are discussed.
When a structure is influenced by the earthquake external force, some energy imposed to the structure is dissipated and remained energy causes structure displacements. Dissipated energy in the structure depends on the type of structure and its optimal engineering design. In any typical structure, the type of connections, stiffness of structure, dampers, place of windfall and damper and other factors play significant role in the amount of dissipated energy. This article introduces a new resilience factor which is a function of energy dissipation factors of input seismic energy. Mathematical equations are presented for this factor and its limits are determined for different periods. The applicability of the proposed factor is also investigated for two typical structural examples.
Various methods are available to reinforce concrete members and structures. Wrapping the concrete beams with composite sheets is one of the suggested methods for increasing the load bearing capacity of concrete beams and specially those containing opening. In this paper, the influence of using two composite sheets reinforced with carbon (CFRP) and glass (GFRP) is studied on increasing the strength of concrete beams having opening. A number of concrete beams with and without openings were modeled in ANSYS and using the nonlinear analyses, the initial cracking load, ultimate failure load, cracking pattern and deflection were determined numerically for each beam. Different wrapping schemes were examined for increasing the load bearing capacity of the opening section and it was concluded that wrapping from both inside and exterior of opening with the mentioned composite patches provide the most enhancement in the opening zone. Also the CFRP patch showed better performance in comparison with the GFRP wrapping.
High performance fiber-reinforced cementitious composites (HPFRCC) are aggregates like cement grout with fine grains and fibers which can be used in many cases like seismic improvement of building components. One of these building components is connecting beam in coupled shear wall which can increase plasticity and energy absorption. In this paper nonlinear finite element model of coupled beam containing HPFRCC is analyzed and the influence diagonal reinforcement is investigated on cracking patterns, stress contours and hysteresis diagrams of shear wall. It was observed that diagonal reinforcements play significant role in shear load bearing capacity of shear wall coupled with HPFRCC beam.