Proper behavior of structures under loads, such as gravity and lateral loads, ensures the needs of the owner and expected performance of buildings during the period of operation. Besides, ensuring the proper performance of the structures during probable earthquake is very essential.
In the usual process of achieving and ensuring the correct behavior of structures under gravity and lateral loads, steps such as “adequately design and construction”, “material quality control” and “material examination and testing” shall be performed. In cases such as “incidence of faults in the design or construction of structures”, “change in occupancy and importance of buildings” and so on, seismic evaluation of existing buildings shall be conducted. If deficiencies are detected in existing structures, to improve seismic performance, seismic rehabilitation and structural strengthening is inevitable.
New building codes are primarily intended to regulate the design and construction of new buildings; as such, they include many provisions that encourage the development of designs with features important for good seismic performance, including regular configuration, structural continuity, ductile detailing, and materials of appropriate quality. Many existing buildings were designed and constructed without these features and contain characteristics such as unfavorable configuration and poor detailing that preclude application of building code provisions for their seismic rehabilitation. Therefore, it is expected that buildings rehabilitated in accordance with seismic rehabilitation codes and standards.
Seismic rehabilitation of buildings shall comply with the design criteria and procedures of the related standards for achieving the performance-based Rehabilitation Objectives.
Seismic rehabilitation of an existing building shall be conducted in accordance with the process including: “Review Initial Considerations”, “Select Rehabilitation Objective”, “Obtain As-Built Information”, “Select Rehabilitation Method”, “Perform Rehabilitation Design” and “Verify Rehabilitation Design”.
In order to reduce the cost of implementation of rehabilitation details, reduction in the volume of structural strengthening is essential. Therefore more accurate calculations such as nonlinear analysis procedures are very useful. While linear procedures are appropriate when the expected level of nonlinearity is low.
Over the past years, MSD has finished numerous projects of Seismic Rehabilitation of Existing Buildings, thereby acquiring a wealth of experience, and is providing expertise for seismic evaluation and rehabilitation of existing buildings, based on codes and standards such as ASCE41-06, ASCE31-03, ACI318-08, AISC360-10, AISC341-10, FEMA-356, FEMA-547, FEMA-440. Also in order to cost efficiency of retrofitting and structural strengthening of buildings, MSD applies the latest technology available in the developed world.