The Mechanical Properties of High Strength Concrete for Box Girder Bridge Deck in Malaysia

This paper presents an experimental investigation of the mechanical properties of high strength concrete for box girder bridge deck in Malaysia. To study the Malaysia condition, high strength concrete samples were obtained from a Malaysian precast concrete factory that provides precast and in-situ concrete for box girder bridge deck construction. The mixed design properties of this type of concrete mixture were investigated; including the slump test, compressive strength, flexural strength, static modulus elasticity and Poisson’s ratio. Stress-strain curve relationship was produced as well, to be used for non-linear behaviour study

Development of elastic design response spectra with emphasis on far‑source earthquakes for low to moderate seismic region

The development of design response spectra is crucial for earthquake design of structures. However, there are disagreements from the engineering community on the suitability of design values proposed by the existing design code which underestimates the long-period responses for fexible soils, typical of far-source earthquakes. This study uses soil response analysis to investigate the efect of near and far sources’ earthquakes on the response spectral acceleration of Malaysia in three seismically diferent regions, namely Peninsular Malaysia, Sabah and Sarawak. 1923 borehole data have been collected and analysed under 5 near and 4 far sources earthquakes, subjected to the intensity from the probabilistic seismic hazard analysis. The results show that for Peninsular Malaysia, the far-source earthquake will govern the response at a period of more than 1 s, indicating its importance for structures with long periods such as tall buildings. It is also found that the corner period TC is slightly higher than the code recommended and is dependent on the soil property, while TD is signifcantly higher for far-source earthquakes due to the larger magnitudes. The fnding of this research shows that the Eurocode 8 supplemented by the Malaysian National Annex (MS-EN1998-1, 2017) can be used to design structures in Malaysia, with some adjustments to the longer period motion for Peninsular Malaysia. Finally, it is recommended to perform an enhanced analysis for important structures of long periods to ensure their loadings are not underestimated

Derivation of attenuation equations for distant earthquake suitable for Malaysia

One of the critical factors in seismic analysis is selecting appropriate attenuation equations. This formula, also known as ground motion relation, is a simple mathematical model that relates a ground motion parameter (i.e. spectral acceleration, velocity and displacement) to earthquake source parameter (i.e. magnitude, source to site distance, mechanism) and local site condition (Campbell, 2002). It is considered one of the critical factors in seismic hazard analysis. It may lead the design load for building either become too conservative or under design. There has been a number of attenuation equations derived in the last two decades since the record of ground motions becomes more available. In general, they are categorized according to tectonic environment (i.e. subduction zone and shallow crustal earthquakes) and site condition. There are several attenuation relationships derived for subduction zone earthquake, which are commonly used such as Crouse (1991), Youngs (1997), Atkinson and Boore (1997), Petersen (2004). Whereas attenuation relationships, which are developed by Abrahamson and Silva (1997), Campbell (1997, 2002), Sadigh et al. (1997), Toro (1997), are frequently used to estimate ground motion for shallow crustal earthquake. The shortcomings of this method are by the limitation of the attenuation relationship itself. Usually attenuation relationship is derived for near source earthquake. Therefore, most of the attenuation relationships have a distance limitation. Except attenuation developed by Toro (1997), and Campbell (2002), all of the attenuations are only valid to be applied for distances between 80 km and 400 km. Since there is no attenuation relationship has been derived directly for Malaysia region, which is affected by long distance earthquake, therefore selection or development of appropriate attenuation relationship for Malaysia is needed. This research is collaborating with related institutions such as Malaysian Meteorological Department (MMD), Jabatan Mineral dan Geosciences Malaysia (JMG) and United States Geological Survey (USGS). There are 481 recordings from 40 mainshocks and aftershocks which magnitude greater than 5.0 in the full data set. Recordings with unknown or poor estimates of the magnitude, mechanism, distance, or site condition were excluded from the data set used in the regression analysis. This reduced the data set used in the analysis to 91 recordings from 14 earthquakes

The mechanical properties of high strength concrete for box girder bridge deck in Malaysia

This paper presents an experimental investigation of the mechanical properties of high strength concrete for box girder bridge deck in Malaysia. To study the Malaysia condition, high strength concrete samples were obtained from a Malaysian precast concrete factory that provides precast and in-situ concrete for box girder bridge deck construction. The mixed design properties of this type of concrete mixture were investigated; including the slump test, compressive strength, flexural strength, static modulus elasticity and Poisson’s ratio. Stress-strain curve relationship was produced as well, to be used for non-linear behaviour study

Assessment of liquefaction hazard along shoreline areas of Peninsular Malaysia

Using a collection of 2074 boreholes extracted from soil investigation reports utilized by standard penetration test, this study examines the susceptibility of soil liquefaction hazard along the shoreline of Peninsular Malaysia. Data collection and site visit were conducted to gather all the basic information related to soil liquefaction hazard. Three types of results are presented in the form of photos (recent shoreline condition), graphical illustrations (soil composition, SPT-N distribution and zone of saturation) and liquefaction susceptibility plots. The findings indicate there is obviously a critical need to adapt further liquefaction analysis in the shoreline region of Peninsular Malaysia to better understand liquefaction hazard and produced beneficial information on the matter. A risk assessment matrix is also introduced in classifying the severity and recommended mitigation measures of the studied areas

Seismic characteristics of X-cable braced frames bundled with a pre-compressed spring

The performance of steel structures can be enhanced against lateral loads by various methods; of these, bracing systems are the most common. Past studies have shown that tension-only braced frames provide more structural stability, and hence offer better resistance when the frame is subjected to lateral loads. In a comparison between a braced and bare frame, the additional efficiency offered by the bracing depends on the selection of bracing system. This paper proposes a cable brace system with a pre-compressed spring (PCS) that bundles the wire-rope bracing members at the intersection point. Both experimental and analytical studies are conducted, and no loosening in the cable is observed, as the cables are held tension by the spring's force; thus the ability of the bracing system to cause impulses is eliminated. The final strength of the cables is reached at larger lateral displacement of the frame compared to ordinary cross cable bracing system. The equations involved in the proposed technique are discussed before being verified using finite element (FE) solutions based on ABAQUS analysis. It can be concluded that the ductility and strength of the tested specimens was significantly improved by means of the proposed technique

Seismic microzonation map of Penang Island

The Peninsula of Malaysia is situated at a distance of 350 km from the seismic zone of Sumatra fault. However, some ground motions are caused by the Sumatra Earthquake. According to the announcements by the Malaysian Metrological Department, the earthquake occurred near Sumatra on 2nd November 2002 with the magnitude of 7.4 had caused tremors in various parts of the Malaysian Peninsula including Penang Island. Penang Island is the most populous island city which is situated in the state of Penang with a rising population of 0.7 million people. Hence, the need for seismic hazard mitigation is evident. In this research, seismic microzonation maps presenting amplification and surface acceleration are plotted to produce a comprehensive microzonation model, to indicate the high risk earthquake areas for land use management. 24 boreholes were located and drilled for data collection. The collected data from boreholes and the bedrock motion obtained were calculated by NERA (Nonlinear Earthquake site Response Analysis), which had generated the surface acceleration and amplification needed for mapping. The results of this paper show the high seismic risk areas on eastern part of the Island that can be used in the planning of urban city infrastructure, which can recognize, control and prevent geological hazards

Investigation of channel shear connectors for composite concrete and steel T-beam

This paper evaluates the behavior of channel shear connectors, embedded in a concrete slab, with different concrete materials. The results of a series of limited push-out specimens were presented and discussed. The push-out tests comprise of channel shear connectors in different types of concrete. Reinforcement was included in some specimens, as well. The results showed that using reinforcements in concrete slab, enhances the ductility and shear capacity of the composite system and using channels embedded in unconfined normal concrete, has a brittle performance. The channel shear capacity is less in the lightweight aggregate concrete, compared to the normal ones. Adequate ductility was reported for the channel shear connectors in most of the concrete types. In addition, it was verified that the channel connector presents a very rigid behavior, during the primary phase of loading. Using channel connectors with longer length can increase the ductility of the system. In general, the channel shear connector showed a ductile behavior. The results verified using channel shear connectors, embedded in tested concrete, in composite structures. The results also discussed the effect of different concrete types, on the ductility and load–displacement performance of the specimens

Seismic Vulnerability of Low- and Mid-Rise Reinforced Concrete Buildings in Malaysia Designed by Considering Only Gravity Loads

This study focuses on seismic vulnerability assessment of reinforced concrete buildings designed by considering only gravity loads. Fragility curves are developed for a three-story reinforced concrete office frame building and a four-story reinforced concrete school building with unreinforced masonry infill walls representative of the essential facilities in Malaysian Peninsula. A simplified modeling approach is adopted for fragility analysis, which can effectively reduce the computational effort. A set of fragility curves are developed in terms of peak ground acceleration with lognormal cumulative distribution functions. The fragility analysis shows that the seismic performance of the structures met the desirable performance level recommended by current seismic code, demonstrating low vulnerability of the structures within Malaysian Peninsula. It is also shown that the soil condition should be taken into consideration for effective seismic vulnerability assessment. Finally, the fragility curves developed in this study are compared to those of HAZUS

Performance of Steel Frame with a Viscoelastic Damper Device under Earthquake Excitation

Standard routes for upgrading existing buildings to improve their seismic response can be expensive in terms of both time and cost due to the modifications required to the foundations. As a result, interest has grown in the installation of viscoelastic dampers (VEDs) in mid and high-rise buildings. Details of a low-cost viscoelastic passive control device, the rotary rubber braced damper (RRBD), are presented in this paper. This design has the added benefits of being lightweight and simple to install. Experimental methods and finite element modeling were used to assess the performance of the proposed VED design and its effect on building response during earthquakes. The analyses took into account the behaviors of non-linear materials and large deformations. The results indicate that the proposed RRBD provides high levels of energy absorption, ensuring the stable cyclical response of buildings in all scenarios considered. In addition, time history analysis was employed in this study to evaluate the RRBD’s ability to control the displacements and accelerations experienced by steel frame structures. It was demonstrated that the device responds well even at low displacements, highlighting its suitability for use in seismic events of varying severity