Civil Engineering Dimension (E-Journal)
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Elasticity of Travel Time and Travel Cost of Private Vehicles and Public Transportation in Bandung, Indonesia
Full text linkUnderstanding mechanism of users in responding determinant variables to use mode of transport is beneficial to anticipate the effect of policy. This study aims to identify the elasticity value of travel time and travel cost of the users of private vehicles and public transportation. Using data from users of private vehicles and public transport in Bandung, Indonesia, the elasticity of travel time and travel cost was calculated based on estimated multinomial logit model (MNL) logit. The elasticity was calculated based on gasoline prices, parking fees, transfer fees, access times, travel times, and waiting times. Based on the results of the elasticity values for travel attribute, it was found that in access time and travel time, Trans Metro Bandung (TMB) Bus had the largest elasticity of -0,564 and -5,001, respectively, so TMB Bus was the most sensitive to changes in access time and travel time. In terms of waiting times and fixed costs/gasoline, conventional taxi has the highest elasticity values of -2,630 and -1,604, respectively, so conventional taxi is the most sensitive to changes in waiting time and fixed costs/gasoline
Strength Properties of Alkaline Activated Phosphoric Acid Stabilized Laterite
Full text linkThis study investigated the effect of alkaline activation on the properties of Phosphoric Acid (PA) stabilized laterite. Maximum Dry Density (MDD), Optimum Moisture Content (OMC), California Bearing Ratio (CBR) and Unconfined Compressive Strength (UCS) of the laterite were determined to ascertain its suitability as a construction material. Laterite samples were stabilized with 1M and 2M PA at 5, 10 and 15%, respectively, by weight of dry soil. Some PA stabilized laterite were further mixed with an alkaline activator. All the stabilized laterites were moist cured for up to 14 days. The results show that the laterite was unsuitable as a road construction material in its natural state. The CBR of PA stabilized laterite improved with about 25%, while that with alkaline activation showed more improvement of up to 145%. The UCS of PA stabilized soil and that with alkaline activation increased with about 250% improvement. In conclusion, alkaline activation of phosphoric acid stabilized laterite soil for road construction has a great promise
Nonlinear Analysis of Reinforced Geopolymer Concrete Beams
Full text linkTo decarbonise the current construction sector and meet the global net-zero target, there is a pressing need to develop an environmentally friendly alternative to Portland cement concrete. Alkali activated and geopolymer concrete have much to offer in this regard. At present, however, there is limited study on the behaviours of alkali activated structural members, particularly on flexural members, which encompass most practical design situations. This paper presents a database of 37 tests on slender alkali activated and geopolymer concrete beams available in the literature, with the aim to investigate the flexural strengths of this alternative concrete when used as a structural member. In addition, the results of nonlinear finite element analyses on fourteen reinforced geopolymer concrete beams are presented to highlight key influencing factors governing the behaviour and failure of flexural members. Of particular interest is to study the influence of reinforcement ratio, compressive strength, and material brittleness on the overall strength and ductility. Overall, it is shown that the flexural response of geopolymer concrete beams under short-term loading is comparable to that of ordinary reinforced concrete beams
Application of Modified-Partial Capacity Design Method on 6- and 15-story Square Buildings with Variation in number of Elastic Columns
Full text linkModified-Partial Capacity Design (M-PCD) is proposed as one alternative of structural design methods. In M-PCD, the partial side sway mechanism where beams and some columns may develop plastic hinges. This method uses two structural models during the design process. The models are used to simulate undamaged and damaged structures when subjected to design earthquake (R=8.0) and larger target earthquake (R=1.6) respectively. In this study, 6- and 15-story square buildings with 30% and 50% elastic column are designed using M-PCD. Performances of the buildings are investigated by using non-linear time history analysis. Results show that the buildings’ performances are still unsatisfactory, especially for the 15-story buildings. However, it should be noted that the levels of earthquakes used for the analysis were larger than that used for the design. A more accurate prediction of the required strength should be developed further to improve M-PCD
Optimization of Water Distribution in Pagerwojo District Tulungagung, Indonesia, using Linear Programming Model
Full text linkOptimization approaches has been utilized in solving complex water service problems. This study attempts to determine the optimal distribution system for clean water pipelines by applying linear programming method which enables the determination of the optimal and most affordable solution under all constraints. The decision variable was the water quantity allocated to the system. The piping investment, operational and maintenance costs in present value with 4% interest were calculated to obtain the water unit price. The allocated water should meet the requirements within a dependable discharge. The study was conducted in Pagerwojo District, Tulungagung Regency, Indonesia, grouped into three transmission lines with 106 l/s demand. There are three sources of fresh water, namely Song River, Klantur River, and Gondang Spring. The analysis reveals that the minimum cost was Rp456,679,296/month. Linear programming method is proven useful for determining the allocation of clean water in the most cost-efficient manner
Deep Well Injection Induced Seismicity
Full text linkInjection of fluid into subsurface geologic strata for geothermal energy, oil production, and waste disposal has been linked to induced seismic activity in the United States as well as in several other countries. According to the report of the National Research Council of United States of America thousands of induced earthquakes were reported at the numerous sites, where oil and gas recovery and waste disposal activities took place. Most of these induced earthquakes were small magnitude events (Moment Magnitude [Mw] < 4), although earthquakes of magnitude (Mw) 6.5 to 7 were also reported near the oil and gas production sites. This paper presents the results of a review of case histories on increased seismic events due to deep well injection (DWI) and oil extraction. Key factors that may lead or contribute to increased seismicity will also be discussed
Locking-free Kriging-based Timoshenko Beam Elements using an Improved Implementation of the Discrete Shear Gap Technique
Full text linkKriging-based finite element method (K-FEM) is an enhancement of the conventional finite element method using a Kriging interpolation as the trial solution in place of a polynomial function. In the application of the K-FEM to the Timoshenko beam model, the discrete shear gap (DSG) technique has been employed to overcome the shear locking difficulty. However, the applied DSG was only effective for the Kriging-based beam element with a cubic basis and three element-layer domain of influencing nodes. Therefore, this research examines a modified implementation of the DSG by changing the substitute DSG field from the Kriging-based interpolation to linear interpolation of the shear gaps at the element nodes. The results show that the improved elements of any polynomial degree are free from shear locking. Furthermore, the results of beam deflection, cross-section rotation, and bending moment are very accurate, while the shear force field is piecewise constant
The Impact of Contractor Safety Leadership on Workers Safety Behavior
Full text linkThe importance of safety leadership for effective management of safety behavior has been acknowledged by many researches. However, its development in construction industry is lagging compared to other industry, especially in Indonesia. This research empirically evaluates the impact of contractors’ safety leadership on construction workers’ safety behavior. It explores three dimensions of safety leadership variable and two dimensions of safety behavior variable, and then examines the relationship between the two variables. Data was gathered through questionnaire survey to eighty-four workers from five on-going construction projects in Surabaya. Multiple regression analysis was performed to examine two models of the impact of safety leadership on safety behavior. The findings suggest that safety concern and safety motivation positively impact safety compliance and safety participation, whilst safety policy only have a significant positive impact on safety participation. The paper discusses these findings and their implications for shaping workers’ safety behavior in construction projects
The Effect of Welded Splice with Predetermined Gap of Concrete Spun Pile on The Response of Low Strain Integrity Test
Full text linkThis paper presents the velocity wave of concrete spun piles with welded splice. The stress wave velocity was recorded using Pile Integrity Test. Two specimens were prepared in the experiment. The first sample was prepared visually no gap between the two end-plates of connected piles, while the second specimen was prepared by inserting 5mm thick steel plate into the splice to create a gap in its connection. The results show that a spike of reflecting stress wave still develops at the splice with and without gap, regardless the splice was welded in full circle. The relatively high spikes of reflecting waves at pile toe are noticed for both specimens with and without gaps. It shows that the full welded splice able to transfer stress wave velocity. A good quality of welded splice can be indicated by the reflecting wave at the pile toe, regardless the reflecting wave development at the splice
Seismic Behaviour of Strengthened Unreinforced Masonry Walls using Kevlar-FRP
Full text linkUnreinforced masonry walls (URM) in old buildings are vulnerable to collapse upon receiving high lateral inertia force due to earthquakes. However, a high strength fiber material such as Kevlar fiber has been identified as able to improve the URM-Wall performance, especially in shear strength enhancement. In this research, the seismic performance of an URM-Wall was analysed using SAP2000 by modeling the wall with three dimensional solid elements. Solids and springs as link connectors were assigned to represent the masonry behavior. The aim of this research is to compare between results obtained from the computer analyses and the previously conducted laboratory experiments. The effectiveness of Kevlar material installed in the diagonal directions of both wall surfaces was investigated. It was found that the failure mechanism shown by the SAP2000 model is similar to the laboratory test results