Applied Mechanics and Materials Vol. 802

Abstract: This paper presents a numerical investigation on the effect of perforation to the steel purlin on bending behaviour. In order to reduce the weight of steel sections, web profile with openings has been introduced in the construction industry, so does the purlin. However, there is no research done on the C-purlin with perforation. Hence, 33 nonlinear analyses were carried out to investigate effect of perforations to the steel purlin on bending behaviour. Yield moment of the steel purlin with and without perforation will be determined. And, effect of various perforation shapes and size on bending behaviour is investigated. Finite element model was developed using software LUSAS. C-channel steel section without opening is used as a control specimen. The results are expressed in term of yield moment. The results show that the edge distance from the opening to the support plays an important role in affecting the moment capacity of C-purlin. Increasing the opening spacing would increase the moment capacity. Number of openings also affects the moment capacity of the section. Octagonal shape with 0.40H and e= 350 mm shows the highest yield moment value with 16.318% higher than that of section without opening. In conclusion, perforation increases the moment capacity of the C-steel purlin.

Abstract: Numerical studies were conducted to evaluate the behaviour of a hollow diamond shaped hysteretic steel plate damper under in-plane cyclic loading. The combine hardening material model based on Chaboche kinematic hardening rule and exponential isotropic hardening rule was proposed to trace the cyclic hardening behaviour of the steel damper. For engineering design purposes, simplified models based on bilinear and trilinear models were also presented. Numerical results showed that hysteretic curve obtained from Chaboche model and the simplified models correlate well with experimental results. Furthermore, the validity of the simplified models is verified through a comparison of its hysteretic energy dissipation with the actual test data.

Abstract: Malaysia has been the largest producer and exporter of palm oil in the world, accounting for 52% of the total world oil in year 2006. The waste disposal problem from palm oil industry was increasing. In addition, the government also facing the problems when forced to allocate more landfill for the disposal of concrete waste. Nowadays, the by-product the palm oil mill has becoming potentially to be utilized as construction material in term as additives for cement. This paper discussed the water absorption and compressive strength of Recycled Aggregate Concrete (RAC) containing Palm Oil Fuel Ash (POFA). There are twelve (12) series of concrete mix containing POFA and recycled aggregate (RA) were used as additives for cement that have been indicated as POFA-0%, POFA-10%, POFA-20%, POFA-30% and RA-0%, RA-50% and RA-100%. The slump test was conducted to determine the performance of fresh concrete. The hardened concrete have been tested its compressive strength and water absorption of POFA-concretes at 7 and28 days of water curing ages. The results revealed that POFA-recycled aggregate concrete has lower water absorption and higher compressive strength comparedto recycled aggregate concrete without POFA. The optimum additional of POFA was 30% for concrete made with 100% natural aggregate (NA) produced higher compressive strength and lower water absorption.

Abstract: This study introduces a practical method for evaluating structural damage based on a large-scale simulation targeting expansive areas, like whole cities. In such a seismic simulation that deals with numerous building structures, it is desirable to estimate the damage based on a stochastic evaluation considering the uncertainty of structural properties. This is because an accurate modeling of numerous building structures, according to each designed value, would require a great deal of time. However, a damage evaluation considering the model uncertainty generally involves numerous calculations and is inadequate for such a large-scale simulation. Therefore, we propose a method using the point estimate technique which can estimate the probability of damage under model uncertainty from a small number of calculations. The applicability and usefulness of the proposed method is evaluated by comparing it to the method based on a Monte Carlo simulation.

Abstract: A precast concrete closed spandrel arch bridge system developed for river crossing in Malaysia is presented. The 7.1m clear rise and 20.1m clear span overfilled arch bridge was proposed. Conventional beam bridge construction system has been ruled out due to the handling difficulty and cost factors. A structurally efficient precast arch section with corrugated shape was conceptualized, designed and developed. The economical viable solution adapted was a precast closed spandrel arch bridge system consisting of two connecting half-leaf panels with insitu crown beam. This system has been proven effective featuring simple precasting technique, handling process and practical jointing system at the crown. Comparisons between Precast closed spandrel arch bridge system and conventional beam bridge system is also highlighted.

Abstract: Most of the rice husk is disposed with no further concern and this has caused waste disposal problems. Burning rice husk can cause health and environmental problem. Rice husk ash has been widely used for concrete technology application as additive in concrete mixture. However there is lack of study on the usage of raw rice husk. This paper presents the experimental on the properties of cement mortar consisting raw rice husk which focused on the porosity and density. Specimens were prepared by incorporating different percentage of rice husk with mortar. Summation of 10 mixes has been investigated to determine the compressive strength, density, porosity and water absorption. As the main purpose of the rice husk cement mortar is for drainage material, the main characteristics needed are porosity and lightweight. From the results, it is concluded that the higher percentage of rice husk used, will decreased the compressive strength and density and increased the porosity of rice husk cement mortar.

Abstract: Dredged marine soils (DMS) are considered as wastes and are currently not being recycled. Solidification of DMS needs to be undertaken before the materials can be reused.This study focused on the development of strength of three solidified fine-grained DMS which are high plasticity clay (CH), high plasticity silt (MH) and low plasticity silt (ML) admixed with cement and bottom ash. This paper discussed the effect of water-binder ratio and curing period on the strength development of the solidified DMS. The results show that the strength increased with prolonged curing. The strength increased when the water-binder ratio was decreased. CH samples with water-binder (w/b) ratio =1 has the highest strength that are up to 4.7 MPa. Optimal w/b ratio for solidified DMS is w/b=3.

Abstract: Corrosion of reinforcement is one of the causes of concrete deterioration by the water contained chloride ions and gas, for example hydrogen sulfide that penetrate into the concrete structures. By performing the related transport properties testing, it will fulfill the main objective of this research that is to investigate the fluid transport and bonding properties between normal concrete substrate (NC) and green USM reinforcement concrete (GUSMRC) containing ultra-fine palm oil fuel ash (UPOFA) as repair material. GUSMRC is the type of concrete that has been upgraded from the ultra-high performance fiber reinforces concrete (UHPFRC) with 50 % of UPOFA replacing the cement. Recently many researchers have found that the POFA can be used as partial cement replacement in the concrete which can improve the durability and also the fluid transportation properties. For the bonding properties, two types of surface treatment / roughness will be perform to investigate the greatest bonding and also the durability between NC substrate that act as an old structures with GUSMRC as new repair material. It’s important to perform the other related testing so that the future results obtained can be conclude either this new green ultra-high concrete can resist the harmful environmental aggression and also if it has an excellent bonding with the old concrete as a repair material.

Abstract: Exposure of concrete to intense heat will cause deterioration of its strength and durability. Previously, the fire-damaged concrete was repaired using the shotcrete and normal concrete. Recent studies utilize fibre reinforced polymer (FRP) in repairing fire-damaged concrete. Ultra High Performance Fiber Reinforced Concrete (UHPFRC) mostly developed using fine size aggregate, cement, silica fume, super plasticizer and reinforced with steel fibre has an excellent mechanical properties compared to high strength concrete and with an addition of steel fibre in the UHPFRC enhances its ductility behaviour which is not possessed by normal concrete, hence, UHPFRC indicates a promising candidate as repair material to fire-damaged concrete. The aim of this paper is to review on the properties of UHPFRC to be utilized as repair material to fire-damaged concrete structure based on previous research on UHPFRC and fire-damaged structure.

Abstract: Failure modes in composite plates with bolted joint configuration include net-tension, shear-out and bearing failures. Few analytical and numerical approaches in strength prediction frameworks of composite plates with bolted joints were reported in the literatures. Present works are dealing with strength prediction in bearing failure of woven fabric CFRP plates with double lap bolted joint configurations by modeling 3D finite element analysis framework. The pre-processing stage is modeled using commercial ABAQUS CAE package and takes into account all parts interactions, clamping pressure and friction contact. Testing series are following the experimental works found from the literatures with variation of plate width to hole diameter (W/d) ratios and incorporated with finger-tight clamp-up. Hashin failure criterion was implemented as constitutive modeling in current analysis, based on ply-by-ply approaches found to be more appropriate phenomenon in bearing failure. The strength prediction results demonstrated good agreement with all experimental datasets particularly with bearing failures as compared with previously reported work, used stress concentration approach found to be accurate in net-tension failure only.