Civil Engineering Dimension (E-Journal)
Not a member yet
443 research outputs found
Sort by
Utilization of low sulfur fly ash from circulating fluidized bed combustion burner as geopolymer binder
Full text linkCirculating fluidized bed combustion (CFBC) is a newer type of burner that employ a circulating process to burn fuel effectively. CFBC burning process is gaining more popularity due to its compact size, high efficiency and lower burning temperature compared to the pulverized coal combustion (PCC) burner. The CFBC burner produces fly ash with different physical properties compared to the PCC burner, i.e. the fly ash is not rounded, and required higher water content for comparable workability. The CFBC fly ash also has a high sulfur content that is detrimental for hardened concrete. Due to its drawbacks, the CFBC hardly used as cementitious material and geopolymer precursor. This study focuses on comparing variations in the concentration of NaOH solution and variations in the ratio of alkaline activators to the setting time and compressive strength of geopolymer mortars on a new class of CFBC fly ash, which have low sulfur content. The concentrations of NaOH solution were 6M, 8M, 10M, and 12M, while the alkaline activator ratios used were 3.0, 2.5, 2.0, 1.0, and 0.5. It was concluded that the low sulfur CFBC fly ash has a potential to be utilized as geopolymer precursor, however, with a shortcoming in its high water demand. The CFBC fly ash used in this study resulted in a geopolymer matrix with good compressive strength and stability. The water demand varies with the fly ash sampling time shows the challenges in the utilization of the fly ash. The highest mortar’s compressive strength, 33.4 MPa at 90 days was achieved at NaOH concentration of 8M and ratio of sodium silicate solution to sodium hydroxide solution of 2.5 with excellent stability
A Virtual Platform to Determine the Tensile Properties of Engineered Cementitious Composite
Full text linkThe four-point flexural test is now making headway as an alternative laboratory investigative technique for determining the tensile properties of Engineered Cementitious Composite (ECC) to the more traditional, direct/uniaxial tensile test. As the fundamental mechanics of ECC specimens tested in four-point flexure are well understood, it is possible to develop a simple relationship between flexural test results and the tensile properties of this cement composite. This paper extends this development and aims to provide accessible and quick calculation of the tensile properties of ECC via a virtual test environment. To this end, attention is directed towards the test configurations developed earlier at Heriot-Watt University, the University of Michigan, and Sepuluh Nopember Institute of Technology. In this paper, the technical background employed in creating the virtual environment and the computer implementation using the JavaScript programming language are presented. The prototype virtual environment is freely available via the Internet at https://ecc-calculator.netlify.app/
Evaluation of a Macro Lump Plasticity Model for Reinforced Concrete Beam-Column Joint under Cyclic Loading
Full text linkLateral deformations of reinforced concrete (RC) frames under extreme seismic excitation are highly affected by the stiffness of their beam-column joints. Numerous models have been proposed to simulate the responses of RC beam-column joint under cyclic loading. Development of RC beam-column joint model based on macro modeling using spring elements becomes more popular because of its considerably simple application for seismic performance evaluation purposes. In this study, a simple modification to previously developed macro-spring element-based model for RC beam-column joint is done and is used to simulate the behavior of seven external and five internal RC joints under cyclic loading in SAP2000. The model consists of several spring elements to define column, beam, joint, and bond-slip responses according to its individual moment-rotation relationships. Overall, the analysis results show that the modified model can simulate well the cyclic behavior of RC beam-column joints when are compared to previously available experimental result
Flexural Strength Behaviour of Apa (Afzeliabipindensis) Reinforced Stabilized Lateritic Soil Beam
Full text linkThis paper reports on the flexural strength behaviour of Apa reinforced stabilized lateritic soil beams. The potential of using timber as a reinforcement material is because timber is abundant, cheap and locally available compared to conventional steel. Apa timber possess a tensile strength of 68.34 N/mm2. Experimental and Finite Element Analysis using ANSYS 15 were carried out to determine the flexural strength of Apa reinforced lateritic soil beams. The results showed an increase in the load-bearing capacity with increase in the percentage area of Apa reinforcement used in Lateritic soil beams. BS 8110-1:1997 requires that area of reinforcement for beams should not exceed 4%. At 4 percent area, the flexural strength of the Apa reinforced lateritic soil beams (ALB) was 0.763 N/mm2 with corresponding load capacity of 3.435 kN which is slightly higher than the steel reinforced lateritic soil beams (SLB) of 0.740 N/mm2 with corresponding load capacity of 3.329 kN obtained in the repor
Numerical Model for High Relative Capacity of Tensegrity Cable Domes
Full text linkThe tensegrity cable domes are a type of structures composed of compressed bars and tensioned cables. They are characterized by an exceptional innovation in terms of lightness. Research in this area is booming towards multiple applications. In the absence of an approach linking design by dimensioning, this article aims to propose a procedure for verifying the design while seeking a better lightness of the structure. The article uses the novelty of the methods applied for this kind of structure, using the hypothesis of geometric nonlinearity, to find the best solution, verifying all the sizing criteria. Through an example of a simple cables dome, we have shown the feasibility of this approach. The shape of the triangles forming the basis of design, have a direct relationship on the relative capacity, this last has been significantly improved, This method can easily be applied to other examples of more complex cables domes
Seismic Vulnerability Assessment Using Rapid Visual Screening: Case Study of Educational Facility Buildings of Jenderal Soedirman University, Indonesia
Full text linkEarthquakes are natural phenomena occurring in various parts of the globe. Severe earthquakes caused substantial loss of life and property when nearly populated districts. Although some progress has been made in the area of seismic prediction, earthquakes in time, magnitude or location can not be estimated correctly. The primary method of reducing casualties is therefore to build seismic resistant structures. Current earthquakes show that the old houses, which are not intended to withstand earthquakes, have been harmed rather than the structures intended according to seismic regulations. Many current structures in Indonesia were intended only without seismic provisions to withstand the gravity loads. There is a need to study these buildings' vulnerability in order to prevent a severe danger. A Rapid Visual Screening (RVS) technique is conducted in this study to determine a Final Level 1 Score, SL1, for Jenderal Soedirman University, Indonesia’s educational facility buildings. In nine constructions situated in Purwokerto and Purbalingga, the method was implemented. Moreover, the final SL1 score is an estimate of the collapse probability if an earthquake occurs with ground motions called the maximum considered earthquake targeted risk, MCER. These score estimates are based on restricted observed and analytical information, thus the probability of collapse is therefore an approximation
Towards Improving Performance of the Construction Industry in Ghana: A SWOT Approach
Full text linkThe construction industry is the second largest contributor to GDP and a significant driver of economic activities in Ghana. Given the importance of the construction industry in boosting the national economy, it is essential to develop effective strategies to keep improving the performance of the industry. To achieve this aim, this research conducted the strengths, weaknesses, opportunities and threats (SWOT) analysis of the Ghanaian construction industry. Underpinned by the SWOT analysis, strategic recommendations are provided to minimise the weaknesses and neutralise the threats that confront the industry, while taking advantage of the strengths and exploiting the opportunities presented to it. These include investment to facilitate innovation and growth, human resource development, development and enforcement of policy and standards, and conducive procurement practice. The recommendations are expected to provide practical and theoretical directions to the industry’s stakeholders on effective ways to improve the industry’s performance
Optimization of resource leveling problem under multiple objective criteria using a symbiotic organisms search
Full text linkBad scheduling and resource management can cause delays or cost overruns. Optimization in solving resource leveling is necessary to avoid those problems. Several objective criteria are used to solve resource leveling. Each of them has the same objective, which is to reduce the fluctuation of resource demand of the project. This study compares the performance of particle swarm optimization (PSO) and symbiotic organisms search (SOS) in solving resource leveling problems using separate objective functions in order to find which one produces a better solution. The results show that SOS produced a better solution than PSO, and one objective function is better in solving resource leveling than the others
Proposed Design Philosophy for Seismic-Resistant Buildings
Full text linkModern seismic design and technologies have undergone tremendous developments. In modern design codes, building structures subjected to high earthquake loads are allowed to experience plastic deformations without collapsing, and the design is permitted up to the ultimate strength. According to comparative results in Japan, the number of humans injured due to earthquakes is higher than the number of deaths/missing. Likewise, the number of residential buildings that collapsed are less than the partially damaged buildings. This outcome implies that residential buildings designed based on the revised seismic standards have good earthquake resistances. It also infers that the human deaths/injury casualties were not a result of the collapsed the structure, but due to the strong vibrations originated from the earthquake, yielding in the collapse of non-structural elements such as ceilings and bookshelves. This paper presents a proposed design philosophy that attempts to implement the effect of earthquakes to non-fatal human casualtie
PEMS-on board and E3 Modeling: A Comparison between Real-World Measurement and Emissions Estimates from Construction Equipment
Full text linkVehicles in construction industry are typically powered by diesel engines and are considered to be an off-road source of air pollution. Air pollutant emissions include nitrogen oxides (NOx), particulate matter (PM), hydrocarbons (HC), and carbon monoxide (CO). Any engine that combusts a nonrenewable carbonaceous fuel will have net emissions of carbon dioxide (CO2). Economic-Energy-Environmental (E3) model, a statistical-modeled tool, is developed by combining a multiple linear regression (MLR) approach for modeling equipment productivity with the emissions calculation algorithm from Environment Protection Agency (EPA)’s NONROAD model. This paper compares emissions data between the field data to E3 model outputs, and determines the similarity of the two sources of fuel use data. It is expected the two data are not narrowly similar since the field data are for individual vehicles, while E3 results are based on NONROAD model, which was intended to estimate average fuel use for a fleet of Heavy-Duty Diesel (HDD) equipment