Design and performance of pre-stressed concrete railway sleepers containing fibres / Afidah Abu Bakar, Khafilah Din and Mat Som Marwi

The design of railway sleepers must account for irregularities of the train or the rails that generate dynamic loads. The sleepers could develop cracks during a train passage although not influential enough to disturb immediately the global track system. However, these cracks can pose a threat to the overall stiffness properties as they can propagate further under repeated loads induced by the train. Consequently they can cause fatigue, which is a structural failure at service condition. This will later constitute a major maintenance item if the problem is not properly addressed. It is intended that the application of highstrength concrete (HSC) with the inclusion of fibres in railway sleepers could reduce, delay or in certain conditions arrest the rate of crack growth. The design of sleeper was proven to comply in partial of the referenced Standards requirements. The fabrication works undertaken also proved that all procedures were followed satisfactorily and that the laboratory of the Faculty of Civil Engineering was able to handle the production. Structural tests carried out where loads were applied at rail seat showed that behaviour of HSFC sleepers had high flexural strength capacities due to the presence of fibres

PSSDB load bearing wall with window opening - effect of butt joint in dryboard / Prof Madya Ir. Siti Hawa Hamzah …[et al.]

Profiled steel sheet dry board or PSSDB system is a new innovative composite construction system with a potential to be expanded in application as an alternative to flooring, wall unit and roofing system. In this study, load-bearing walls with window opening were constructed using PSSDB. The investigation was carried out experimentally to determine the structural behaviour and to see the effect of butt joint in the dry boards. The PSSDB load bearing wall system consists of two dry boards (Cemboards) attached to profiled steel sheet (Bondek II), the core of panel, using mechanical connectors (self-drill screws). Several aspects such as literature review, testing method and analysis of results were included in this research. The samples tested were three (3) numbers of PSSDB walls with window opening and butt joint in the dry boards, and three (3) numbers of PSSDB walls with window opening but without butt joint in the dry boards. The size of each sample is 1000 mm high x 1320 mm wide x 78 mm thick with window opening of size 400 mm x 400 mm x 78 mm. The connectors were fixed at a 100 mm center to center in the longitudinal axis. The samples were subjected to axial compressive load and comparisons were made between the two sets of samples. The average value of the ultimate load capacity for PSSDB load bearing wall with butt joint was* found to be 286 kN, while that for the samples of PSSDB load bearing wall without butt joint was 260 kN. The maximum lateral deflection values for both types of PSSDB walls were 10.7 mm and 13.5 mm respectively. Significant effect of butt joint in dry board were seen in the reduced number of cracks by about 33% in comparison to that without butt joint

Exfiltration from sewers: effects of different types of leakage / Mohd Ashaari Ab Wahab ... [et al.]

This research was conducted to study exfiltration of wastewater from gravity sewers. Exfiltration through different types of sewer leaks were studied. With the different size of leakage areas and a constant thickness of soil bedding, it was found that the exfiltration rate reduces and became constant over a duration of one (1) to three (3) days. Knowing the exfiltration rate, the time taken for the polluted water exfiltrate from sewer pipes to reach the groundwater can be determined so that preventive measures can be taken to prevent it. From studies conducted, it can be shown that the size of the leakage area was found to play an important role in determining the size of the clogging zone, the increased in the clogging zone resulted in the decreased of exfiltration rate due to the accumulation of organic matters at the edge of the leakage area and trapped in the pores of the bedding soil

The effect of butt joint on the structural behaviour of PSSDB wall panel / Siti Hawa Hamzah ... [et al.]

An experimental investigation was carried out to determine the effect of butt joint on the structural behaviour of profiled steel sheet dry board (PSSDB) load bearing wall with window opening. The samples tested were three (3) PSSDB walls with window opening and butt joint in the dry boards, and three (3) PSSDB walls with window opening but without butt joint in the dry boards. The samples were subjected to axial compressive load and comparisons were made between the two sets of samples. The average value of the ultimate load capacity for PSSDB load bearing wall with butt joint was found to be 286 kN, while that for the samples of PSSDB load bearing wall without butt joint was 260 kN. The average maximum lateral deflection values for both types of PSSDB walls were 8.9 mm and 13 mm respectively. Significant difference due to butt joint in dry board was seen in the reduced number of cracks by about 33 % in comparison to that without butt joint