Civil Engineering Dimension

Front Matter (Cover, Note from the Editor, Table of Content)

Civil Engineering Dimension — 2024-03-06

Prediction of Soil Expansivity with Direct and Indirect Method in Banten Region, Indonesia

Arlyn Aristo Cikmit — 2024-03-06

Expansive soils are widespread in Indonesia, particularly in Banten Province, causing extensive road damages. The study aimed to predict the soil expansivity of soil subgrade along the damaged road segments in Malingping, Cikeusik-Cibaliung, and Labuan districts. Indirect and direct expansivity predictions were employed to determine soil swelling potential. Indirect expansivity prediction was conducted based on various criteria using the Atterberg limit and grain size distribution. Direct expansivity prediction was conducted using an oedometer apparatus to measure the expansion index according to ASTM D-4829. A dynamic cone penetration test was also conducted to measure CBR values. Various indirect methods showed inconclusive results of swelling potentials, low to very high. The direct method provided more conclusive results, Expansivity Index = 100-167 and swelling values = 9%-18%, thus, categorized as expansive clay (high to very high swelling potential). CBR values were 1.49%-5% which is lower than minimum provisioned CBR (6%).

Evaluation of Shear-Flexure Interaction Behavior of Reinforced Concrete Wall

Jimmy Chandra — 2024-03-06

Reinforced concrete (RC) wall is a critical structural member that resists lateral loadings, such as earthquake and wind. RC wall having moderate height to length ratio, 1.50-2.50, has the altered shear-flexure interaction (SFI) behavior, so shear and flexural failure mechanisms occur almost concurrently. Therefore, an experimental study of a moderate RC wall was conducted as a comprehensive study of the wall’s coupled nonlinear shear-flexure behavior under cyclic loading. The experimental results show that the RC wall failed in flexure mechanism, indicated by crushing of the flexural compression zone, and followed by immediate shear failure, notified by the occurrence of web crushing. In addition to the experiment, an analytical model using SFI-MVLEM element in OpenSees software was performed to verify the experimental results. The analytical results show that the model is able to simulate reasonably well the coupled nonlinear shear-flexure behavior of the RC wall subjected to cyclic loading.

Free-Vibration and Buckling Analyses of Beams using Kriging-Based Timoshenko Beam Elements with the Discrete Shear Gap Technique

Foek Tjong Wong — 2024-03-06

A family of locking-free Kriging-based Timoshenko beam elements with a new implementation of the discrete shear gap technique was recently developed (referred to as K-beam-DSG1 elements). Performance of the K-beam-DSG1 elements has been shown to be very satisfactory in the linear static analysis of beams for a wide variety of thicknesses. This paper presents further development of the K-beam-DSG1 elements to free vibration and bifurcation buckling analyses of prismatic and non-prismatic beams. Consistent Kriging-based mass matrices are used for free vibration analysis and similarly, consistent Kriging-based geometric stiffness matrices are used for buckling analysis. The results show that for most of the cases, the K-beam-DGS1 elements yield remarkably accurate natural frequencies and critical compressive loads using a reasonable number of elements to discretize the beam. For an axially functionally graded fixed-fixed supported beam, however, the elements fail to predict the critical load accurately.

Monitoring and Analysis of Coastline Changes in the Coastal Area of Bali Island, Indonesia

Ni Nyoman Pujianiki — 2024-03-06

Erosion and accretion occuring in coastal areas are indications of changes in the coastline’s position. The beach areas in Bali have high economic value as tourist attractions; yet, the condition of the beaches in several places on the island is very concerning. Monitoring shoreline changes can be accomplished using remote sensing technology which is more efficient than the conventional methods. This paper describes the results of changes in the coastline from 2014 to 2021 with remote sensing for all coastal areas of the island of Bali surveyed in the field. This research has successfully detected changes in coastlines throughout the coastal areas of Bali Island by remote sensing method and verified by field survey. The survey results also show that remote sensing method has met the survey from previous studies specifically in Gianyar Regency and Jembrana Regency. Hence, it is applicable for further use in other areas.

Laboratory Study on Vallejo and Scovazzo’s Methods in Estimating the Rheology Parameters of Bentonite and Kaolinite Muds

Budijanto Widjaja — 2024-03-06

The mud undrained shear strength and viscosity are the essential parameters in understanding the behavior of mudflow. One of the laboratory test methods to estimate the undrained shear strength and viscosity is Vallejo and Scovazzo’s cylinder strength meter test (CSMT) and flume channel test, respectively. This paper compares the undrained shear strength of kaolin and bentonite muds obtained from the CMST to those obtained using the fall cone and mini vane shear tests and also studies the scale effects in the flume channel test in measuring the mud viscosity at a 20^o to 40^o slope angles and at various liquidity indexes. The results exhibit that CMST could estimate the undrained strength of mud as low as 0.45 kN/m²with a liquidity index of up to 5.93. Then, the reduction of the size of the flume channel by half resulted in a mud viscosity of about 2.3 times higher.

Experimental Study of Two-way Half Slab Precast Concrete using Rextangular Rigid Connection

Djoko Irawan — 2024-03-06

A half-slab precast concrete (HSPC) system with precast bottom layers and in-situ cast top layers has been widely applied in various constructions. It generally behaves as a one-way slab due to the absence of positive-flexural reinforcements in the perpendicular direction to the precast component. However, in some cases, the HSPC was also applied in a two-way slab system. Consequently, a particular design and treatment in the connection between precast members was required, so that the bending moment in two orthogonal directions could be accommodated. In the present study, an innovative rectangular rigid connection (RRC) in a two-way HSPC system was investigated through an experimental test. It was found that the RRC-HSPC presented only a 9.13% reduction of the load at the crack, a 16.44% reduction of the ultimate load, and a 6.06% increase of the deflection at the crack when compared to the monolithic one.

Flexural Strength of RHS Perforated Lean Duplex Stainless Steel Beam at Temperature 24-900ºC

Kelsen Andrian Priestley — 2024-03-06

The investigation of stainless steel structures at elevated temperatures is still limited, especially to those focused on the behaviour of perforated beams. Therefore, a numerical study was conducted to investigate the behaviour and strength of cold-formed lean duplex stainless steel (CFLDSS) beams having a single web perforation that failed due to pure bending at temperatures between 24-900^oC. In total, 200 square and rectangular hollow sections (RHSs), which had various cross-section sizes, hole diameters, and temperature simulations, were involved in the parametric study. The numerical study was based on the ABAQUS simulation results of the 200 specimens. The numerical model was developed based on the validated existing studies. Numerical evaluations show that the existing codified strength predictions are conservative, but it has inconsistent safety. Hence, this study suggests modifications to the existing strength prediction, which is more conservative and reliable.

Influence of Prefabrication on Job Satisfaction in The Construction Industry

Lauren Chandler — 2024-03-06

New construction approaches, such as prefabrication, have been increasingly recognised as a strategy to boost productivity and support the industry’s sustainability and growth. Advancing existing understanding on the benefits of prefabrication to promote its adoption, this research aims to assess job satisfaction and work conditions of construction practitioners involved in prefabrication and assess its impacts on their job satisfaction, represented by job demands, job support, physical work environments, and job perception. Quantitative data were collected from 37 practitioners exposed to prefabrication and 30 practitioners involved in conventional construction. The findings show that prefabrication can lead to higher job satisfaction and better work conditions than conventional construction. Compared with conventional construction, practitioners working in prefabricated projects experienced improved workload distribution, better physical surroundings, and positive job perception. This research, therefore, provides new insights into the benefits of prefabrication and its potential to promote better mental wellbeing and higher productivity.

Stress Analysis of Pin Connections in Steel Box Girder with the Unibridge System using Finite Element Model

Ayu Sinta Aprilia — 2024-03-06

This study analyzes the Unibridge system, a modular steel box girder employing two pins for longitudinal connections, thereby expediting construction compared to traditional girders. A finite element model was developed to analyze the stress on these pins in a single-box girder with five segments and a reinforced concrete floor slab. Various loads were applied following the Indonesian bridge loading standard, SNI 1725:2016. The model considers operational load analysis and assumes full composite behaviour between the top flanges of the girder and the concrete floor slab. The results indicate that the Von-Mises stress on the pins reaches a maximum of 490.95 MPa under combined service loads, consistently remaining below the specified material yield stress limit of 1200 MPa. Consequently, the Demand Capacity Ratio (DCR) is 0.41. As a result, the Unibridge girder connection pins do not experience plastic deformation under the applied loads.