A Case Study on Structural Failure of Reinforced Concrete Beam-Column Joint After the First Significant Earthquake Impact in Malaysia

This paper presents a case study regarding failures of structural buildings which occurred in Malaysia after the first significant earthquake event dated on June 5, 2015. Ranau is a locality situated in Sabah, Malaysia on the island of Borneo. The seismic activity was triggered when an earthquake with a magnitude of 5.9 afflicted Ranau, including seven other districts that also felt the tremors. Even though the impact of magnitude was undisputedly not high, the severity level of damages was found to be absolute (irreparable) in the structural RC beam-column joints and soft-storey buildings. Most of the buildings in Malaysia were built without the consideration of seismic design, and thus a major factor in structural failure. The earthquake has directed the seismic demand, while the total displacement was concentrated at the weakest floor that caused more damage to the building.  This paper shows the causes of beam-column joint damages and explains the proposed (to-date) strengthening methods. Future studies related to seismic activities are in need to analyse the performance of the existing design of structural RC members and propose a seismic design in Malaysia

Damage Index Seismic Assessment Methodologies of URM Buildings: A State-of-the-Art Review

This paper is written to review the previous studies of developing Damage Indices (DI) for Unreinforced Masonry (URM) Buildings. DI was designed to provide a critical indicator of damage states (DS), seismic vulnerability, and structural occupancy of buildings. DI approaches with simplified assessment methods to predict seismic vulnerability of URM structures are presented in this review, with the pros and cons of each assessment method are highlighted to propose an ideal methodology in using DI assessment.  Thus, this paper is intended to provide a comprehensive information related to the state-of-the-art of DI methodology that can be used to seismically assess of URM buildings

Assessment of seismic scenario-structure based limit state criteria for a reinforced concrete high-rise building

Issues regarding reinforced concrete (RC) high-rise buildings involve different seismic scenarios, such as near- and far-field earthquakes, which can result in different levels and complex seismic scenario structures related to global damage. This study aims to evaluate the seismic scenario structures of a 23-storey RC high-rise building based on different damage measures and to develop a fragility curve with different limit state criteria. Six ground motions are selected to represent two seismic scenarios. Seismic scenario-based global response of the building at increasing earthquake intensity measures is adopted using incremental dynamic analysis (IDA). IDA curves and interstorey drift are used in the parametric study. The structural performance and damage measure of RC high-rise buildings are evaluated with performance-based seismic design limit state. The four performance levels proposed by ATC-43 are operational performance, immediate occupancy, life safety and collapse prevention. The IDA curves showed that near-field effect has a high frequency that gives impact at early intensity measures on building collapse compared with far-field effect. Meanwhile, interstorey drift result indicates that the near-field effect has a larger effect on building damages compared with the far-field effect. Based on the fragility curves, near-field earthquakes have a larger effect towards structural damages than far-field earthquakes

Investigation of Site-Specific Shear Wave Velocity for Geotechnical Engineering Applications Using Microtremor Array Measurement

Microtremor array measurement surveys were performed in three locations to determine the shear wave velocity profile down to a depth of 30 m. The shear wave velocity results from the data acquisition of the multichannel surface wave method were compared with the microtremor array measurement in terms of the shear wave velocity profile as a function of depth. The correlation indicated that the shear wave velocity values range from 200 to 300 m/s and showed a significant velocity contrast at a shallow depth

Feasibility Evaluation of Novel High-Damping Rubbers as Energy-Dissipation Material under Axial Dynamic Load for Damper Devices

High-damping rubber (HDR) material has been widely used in bearings for seismic-isolation devices in structures. Nevertheless, HDR has not yet been developed in dampers to reduce the response of structures to earthquake excitations by dissipating the energy applied to the structures under direct axial load. The purpose of this paper was to evaluate the feasibility of using novel hyperelastic composite material (HECM), which is an HDR material, in experimental investigations to determine its damping ratio, compressibility, and elasticity behavior under axial dynamic load for the development of novel dampers in the future. First, a series of tests on HECM was conducted using the double-shear method to determine the most suitable sample for a purely dynamic compression test. Subsequently, the HECM was used in a device working as a scaled-down damper under both direct tension and compression dynamic load conditions, and pure direct compression dynamic load conditions were tested. Various thicknesses of the HECM (6, 8, and 10 mm) used in the testing damper were examined under a constant force with various frequencies of 0.01, 0.1, 0.25, and 0.5 Hz. The results show that the 10 mm thick HECM can provide a high damping ratio of 10% to 13% under axial conditions. Hence, this study is important for evaluating HECM, which has the potential for use in developing a full-scaled rubber damper system to resist axial force in the future. The damper is a novel rubber damper with high damping capability to dissipate energy under axial load. Furthermore, the damper can serve as an alternative choice that is more durable and overcomes the current weaknesses of passive dampers

Investigation of Shear Wave Velocity by Using Multi-Channel Analysis of Surface Wave Method for Microzonation Map Development and Its Application to Industrial Frame Structures

The present study focuses on determining soil dynamic property, specifically the shear wave velocity at the top 30 m, to establish seismic microzonation maps and to evaluate the effect of soil flexibility on the frame structures of industrial building design in terms of drift. The model of industrial building steel frame was built on the basis of a 3D model using the SAP2000 software. The applications of spring stiffness for rigid footing spring constraints include average shear wave velocity to define the shallow foundation of the structure. The flexible- and fixed-base models were developed to evaluate the structural performance

Fragility Curves of Regular and Irregular Moment-Resisting Concrete and Steel Frames

This study presents the fragility curves of regular and irregular moment-resisting frames using different heights, materials, and ground motion records. The concrete and steel frames used in this study differed in terms of height, namely, 3, 6, and 9 stories. Each type of frame was designed based on Eurocode 2 and Eurocode 3 with the aid of Eurocode 8 for earthquake loading. Incremental dynamic analysis (IDA) was conducted for the three selected ground motion records using SAP2000 software as the main tool. The IDA curves were compared to the five levels of the limit state of FEMA 356: operational phase (OP), immediate occupancy, damage control, life safety, and collapse prevention (CP). Based on the analysis of fragility curves, irregular frames exhibited a higher probability of reaching OP and CP levels compared with regular frames

Soft Storey Effects on Plastic Hinge Propagation of Moment Resisting Reinforced Concrete Building Subjected to Ranau Earthquake

On 5th June 2015, a moderate earthquake with Mw 5.9 hit Ranau, resulted in damages of the existing nonseismically designed buildings, such that 61 buildings, including mosques, schools, hospitals and Ranau police headquarters were suffered from different level structural damages. Soft storey irregularity is one of the main reasons of the building damage. This study is to investigate the soft-story effect on the propagation path of plastic hinges RC building under seismic excitation. The plastic hinges formation and seismic performance of five moment resisting RC frames with different infill configurations are studied. The seismic performance of building is evaluated by Incremental Dynamic Analysis (IDA). Open ground soft storey structure shows the lowest seismic resistance, collapses at 0.55g pga. The maximum interstorey drift ratio (IDRmax) in soft storey buildings ranging from 0.53% to 2.96% which are far greater than bare frame ranging from 0.095% to 0.69%. The presence of infill walls creates stiffer upper stories causing moments concentrate at the soft storey, resulting the path of plastic hinge propagation is dominant at the soft storey columns. Hence, the buildings with soft storey are very susceptible under earthquake load