Asian journal of civil engineering
Volume:14 Issue: 5, Oct 2013

This paper presents a statistical analysis for evaluating the four most common torsional analytical models of concrete beams strengthened with fiber reinforced polymer. For this aim, data are collected from experimental works and the results predicted by four analytical models are compared with the experimental results. The most appropriate analytical model is selected and is used for determining resistance factors conducting reliability analysis. The second purpose is to study load and resistance factor design calibration for the selected model. Two possible target reliability levels have been chosen from the literature and, an iterative procedure is used for resistance factors calculation.

Fatigue testing is commonly conducted using the single-edge notched beam (SENB) test, which is not simple to prepare. With the widely use of Superpvae gyratory compactor with its consistent circular compacted samples, the industry is keen to find ways to utilize these samples in testing. Therefore, the semi-circle notched beam (SCNB) fatigue test setup was introduced. However, there are no justified design criteria and/or standard test procedure to evaluate fatigue life of asphalt mixes using SCNB. Thus, there is a critical need for understanding the effect of the significance of each controlling testing parameters to evaluate Superpave mixes resistance to fatigue cracking using SCNB. In this study, common testing parameters were investigated and the failure point due to fatigue was clearly defined. In addition, when comparing test results to the Asphalt Institute (AI) model, it was found that the cyclic load range of 30% to 60% of the ultimate strength could be utilized as an appropriate range with a loading frequency of 1 Hz, at which test results illustrated that strain rate and loading range lay within reasonable range of AI design guidelines.

Emission of CO2 into atmosphere has been the main reason behind global warming. Production of one tonne of cement approximately emits one tonne of CO2, the Greenhouse gas and major culprit for global warming, into atmosphere. Global warming is a great concern to humankind, and Scientists throughout the world do extensive researches to find out alternate green materials that could help in reducing the effect of global warming. Fly ash, once considered a waste material, has found usefulness in replacing cement up to 60% and experiments are conducted to determine the fracture parameter of plain cement concrete (OPC) and high volume fly ash concrete (HVFAC). The Beams of size 1200mm long x 100mm wide x 200mm deep are cast for the experiment. The critical Crack Tip Opening Displacement for plain cement concrete (OPC) and high volume fly ash concrete (HVFAC) are determined. Four numbers of M30 grade concrete notched beam specimens are cast with OPC concrete as reference specimens and four specimens each for 50% and 60% replacement of cement with fly ash are also cast. All the beams are tested under three point loading until failure. The parametric study of notch to depth ratio is kept as 0.2 and 0.3. From the test results, the rupture load of the specimens decreased with the increase in fly ash content.

This paper focuses on probabilistic nonlinear dynamic analysis of a plane frame in which density, modulus of elasticity and section dimensions are random variables. The Monte Carlo method is used to simulate the random variables with different types of probability density functions and various coefficients of variation. The time-displacement responses of the frame show that randomness in the material and geometric properties can lead to significant uncertainty in the maximum response displacement. Also, the statistically dynamic responses obtained by the present approach will be useful for studying the structural safety and reliability.

This paper exposes a design methodology for building renewal, which is oriented towards adding sustainability, value, and flexibility. It considers environmental and economic feasibility based on embodied energy in materials, conventional budgets and hedonic price models. A process of design simulation was developed, focusing on a typical housing estate, in Porto Alegre, Brazil. The main results of which indicate that there is potential for increasing their value. Building renewal is a form of recycling and has influence on social, economic, and environmental issues. This work contributes to the discussion of alternatives to the low income housing deficit in Brazil.

Seismic response of isolated bridge under several earthquake ground motions is presented in this paper. Non-linear time history analysis is carried out for both non-isolated and seismically isolated bridge. Lead rubber bearing is employed to observe the isolated bridge behavior. Takeda trilinear model is used to model the mechanical behavior of the pier and simple elastic model is applied to model remaining portion of the bridge. Four different earthquake ground motions are considered and applied at the longitudinal direction of the bridge. It is found that the effectiveness of base isolation technique is highly influenced by the properties of the isolated bridge as well as by the ground motion. It is also revealed that to understand and design efficient isolated bridge system, analyzing the ground acceleration in frequency domain could be more efficient than time domain approach.

The September 18, 2011 earthquake that occurred near the Nepal-Sikkim border had a moment magnitude (Mw) of 6.9. This shallow-focus earthquake lasted for about 30-40 seconds and affected several areas of Nepal, India, China, Bhutan, and Bangladesh. This paper presents lessons learned from the investigation of the performance of buildings in the earthquake affected areas in Nepal. Many non-engineered stone masonry, brick masonry, and reinforced concrete buildings suffered heavy damage, while engineered reinforced concrete buildings and buildings constructed with indigenous technology locally known as Centibera buildings, exhibited minor or no damage.

This paper presents a methodology to make informed decisions for seismic retrofitting considering risk management and expected economic benefit based on seismic loss estimation. Three performance measures: Repair cost, Casualties, Downtime is considered for loss estimation. Time-based performance assessment is used with utilizing Performance Assessment Calculation Tool (PACT). By using probabilistic framework, Annual Loss (AL) has been estimated. AL within a reasonable relationship is combined with retrofit cost and discount rate to obtain the amount of net losses and minimum time required for the economic feasibility of each retrofit alternative. The prescribed methodology is used for assessing the steel resisting frame that has been retrofitted with three different methods. According to this study, various retrofit strategies will have reasonable comparability and loss estimation eases decision process for stakeholders.

Buildings consume a lot of operational energy primarily due to its cooling requirements.Increasing consumption of energy has led to global warming resulting in ozone layer depletion. The key to conserve energy in buildings is to design buildings according to climate. Since most of the population in India is concentrated in hot and arid region, substantial amount of energy can be conserved using proper climatic design. In this paper basically three important climatic design strategies namely shading, thermal mass and courtyard and their significance in climatic control and conserving energy in residential buildings in hot and arid regions has been discussed.

The aim of this study is to investigate the feasibility of using waste bricks powder of Gachsaran Company in concrete. Cement is replaced by waste bricks powder in different proportions until 40 percent by weight. pozzolanic properties of bricks powder and compressive strength of concrete were investigated. The results demonstrated that the bricks powder show pozzolanic properties. Results also show that concrete with partial cement replacement by waste bricks powder has minor strength loss. The results of the investigation confirmed the potential use of this bricks powder material to produce pozzolanic concrete.

Prestressing steel has been popular in the recent past, due to the developments in the field of anti-corrosive coatings. The literature substantiates the application of technique of prestressing to steel structures both in safety and economy point of view. However, for all design calculations, the maximum allowable span for a given load carrying capacity is based on maximum deflection which is calculated by principle of superposition (considering the effect of prestress and total load individually). This paper proposes a method of arriving at expression for deflection of simply supported, prestressed homogenous steel I-beams calculated by considering the combined effect of prestressing and total load. A straight tendon configuration with an eccentric prestressing force is considered for study.

High performance concrete (HPC) is popular for its low water-to-cementations materials ratio (w/cm). Because of this low w/c ratio and rapid hydration, proper curing is essential at the earliest time. This paper explores the use of Super Absorbent Polymers (SAP) and Light Weight fine Aggregates (LWA) as internal curing material. Mix M2 is achieved by adding SAP at 0.3% weight of cement and in mix M3 is obtained by replacing 25% weight of LWA to fine aggregates. Strength and durability of these HPC are studied experimentally and the results show greater strength with LWA mix. Load carrying capacity of the beams in flexure and shear also greater in LWA mix and the durability study results reveal that mix with SAP is better compared to the other two mixes.