Search

The Pacitan Regency of Indonesia is located in an area of high seismic activities. Regrettably, field surveys held in Pacitan Regency, Indonesia have revealed the prevalence of low-income housing structures that do not meet the engineering standards and are vulnerable to damage during earthquakes. The seismic evaluation of these buildings is urgently required. This study proposes realistic damage state limit values for the seismic damage evaluation of non-engineered buildings. For this purpose, an incremental dynamic analysis was conducted on a sample of non-engineered buildings in Pacitan to evaluate their probable seismic damage. As a result, curves showing the dynamic pushover responses of buildings to various input earthquakes were plotted. These curves were then summarized as three-linear curves, providing a single value for the average response of the structure. Based on this simplified curve, a more realistic damage-state limit for non-engineered structures are proposed. The damage levels of slight (DS1), moderate (DS2), extensive (DS3), and complete (DS4) were determined using the drift ratio at the linear elastic limit, midway point between the linear elastic and yield limits, yield state, and 80% rupture limit, respectively.

The modern era witnessed an urbanization and economic growth concentrated in urban areas. Despite an increase in welfare, this receives a greater threat when an earthquake occurs. This research aims to assess the structural risk of low to medium-rise reinforced concrete building structures, commonly built in developing countries. This research was carried out by performing an incremental dynamic analysis (IDA) od an existing building model. In this analysis, the structural model was given a set of dynamic earthquake loads which were increased in magnitude according to certain scale rules until the structure experienced nonlinear behavior and reached a near collapse condition. Five artificial accelerogram recordings were applied on the structure after matching with the spectral response of the target location of the structure. From the analysis, the IDA curves were obtained which describes the global dynamic behavior of the structure, namely displacement due to earthquake lateral loads. Then the damage limits were determined on the IDA curve based on the HAZUS criteria. Then the seismic risk was expressed by constructing a seismic fragility curve. This curve states the probability of exceeding certain damage limits due to variation in earthquake intensity during the service life of the structure.

Non-engineered buildings (NEBs) are prone to earthquake damage. One type of damage that often occurs in NEBs is the separation of beam and column elements owing to joint failures. Strengthening joints with steel plates is expected to improve the seismic performance of this type of building. Strengthening with steel plates is cheap and easy to apply, so it will be a preferable choice in preventing damage to the NEB due to earthquake loads. This study investigated the seismic performance of reinforced concrete frames, representing an NEB whose beam–column joints were strengthened with L-shaped steel plates. Two widths of L-shaped steel plates were proposed: 75 mm (NEB-075) and 100 mm (NEB-100). An NEB without strengthening (NEB-000) was used as a control. Both experimental and numerical investigations were performed to determine the seismic performance of NEBs. The results showed that damage to the NEB-000 and NEB-075 models occurred at the joints, but less damage was observed in NEB-075 than in NEB-000. Furthermore, damage in the NEB-100 model occurred at the column. The undamaged limit levels of the NEB-000, NEB-075, and NEB-100 models were 56.49, 81.54, and 82.46%, respectively. These results show that strengthening the NEB with steel plates effectively improves its seismic performance. According to an analysis of the performance of the tested models, the NEB-100 model exhibited the best seismic performance. [ABSTRACT FROM AUTHOR]

In order to achieve satisfactory global seismic behaviour of a concrete fame structure and to prevent undesirable local failures of its structural element, local strengthening of structural members by means of FRP wrap is one of the cost effective retrofitting strategy. This FRP wrapped column will increase the ductility of the element as well as the capacity that in turn will allow attaining more energy dissipating global performance. This on-going research aims to demonstrate the seismic performance of Low-to-Mid-Rise Concrete Frame retrofitted by FRP wrap in several configurations. The fragility curves of the structure before and after to local strengthening will be developed and analysed. Fragility curve will describe the probability of the structure that will exceed certain damage states given the ground shaking intensity during its service life. This curve allows evaluation for the retrofitting strategy is carried out rationally.

Masonry infilled reinforced concrete frames are a structural system commonly used for low-to-mid-rise buildings. Generally, this type of structure is modelled as an open frame neglecting the strength and stiffness contribution of the masonry infilled panel. In order to describe realistic behaviour under lateral loading, this paper evaluates the seismic performance of the building by modelling the contribution of masonry as a compression strut acting diagonally in the panel. The non-linear static procedure is employed by subjecting the building to pushover loads. The performance of the building is then analysed based on the obtained capacity curve. Seismic performance is assessed in terms of building fragility which is the conditional probability of exceeding certain damage state for a given ground shaking intensity. Fragility functions eventually are expressed as series of log-normal curves of both the open and masonry infilled reinforced concrete frame. Based on this study, the infilled frame can resist a maximum load of 20.3x103 kN, while the open frame is only able to withstand a maximum load of 15.2x103 kN. From the fragility curve, it can be concluded that the probability of the infilled frame to reach a certain damage state is lower than that of the open frame.

Bridge with concrete pier and deck is a conventional highway infrastructure built and utilized in Indonesia. More than half of these typical bridges have been in service more than 20 years. Evaluating these sort of bridge subject to various intensity of earthquake in its future service life is important. This assessment helps owner to predict damages and economic losses due to earthquake as well as to plan and devise seismic rehabilitation intervention prior to the event. The analysis uses fragility function describing the probability of exceedance of certain damage level due to single predictive demand parameter or earthquake intensity measure, i.e. spectral acceleration on bridge structure. The concrete bridge was modelled deterministically with 3-D computational structural model. Analytical non-linear static and non-linear dynamic pushover (incremental dynamic analysis) was employed to determine the structural response. Fragility function eventually is expressed as series of log normal curves which can be used to assess the seismic risk of the bridge considered.

Under the influence of aggressive environment, structural concrete could exhibit degradation in various forms. One of the symptoms of the degradation could be shown in the form of local delamination of concrete cover. Patching method could be a preference choice to repair this type of degradation to regain its structural performance and durability. This paper presents the structural behaviour of patched-reinforced concrete beam under flexural loading with particular interest on the use of unsaturated polyester resin (UPR) mortar as patch repair material. The repair area is replicated in the tensile zone of the beam. The behaviour investigated in this study is the cracking evolution of the patched – reinforced concrete beam and its effect on the deflection. It is shown that the higher strength of the UPR-mortar leads to a reduction in the intensity of cracks compared to that of un-repaired (normal) reinforced concrete beam. The lesser cracks intensity is beneficial to restore the flexural stiffness of the beam.