Civil Engineering Dimension (E-Journal)
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Seismic Vulnerability Maps of Ratu Agung District, Bengkulu City, Indonesia
Full text linkDuring the 8.6 Mw Bengkulu-Mentawai Earthquake Ratu Agung District was identified as an impacted area. This paper aims to deliver the seismic vulnerability based on geophysical observation. This study was initiated by performing the ambient noise measurement to obtain the geophysical characteristic, such as amplification and predominant frequency. Furthermore, the vulnerability index analysis was performed from the geophysical information collected from the investigation. To observe the tendency of ground damage during the earthquake, ground damages analysis is also performed. All results are depicted into the microzonation maps. The results showed that the amplification and predominant frequency on site are generally ranging from 3 to 5 and 5 to 8 Hz, respectively. The seismic vulnerability index in study area is up to 10-3. The results showed that during the Bengkulu-Mentawai Earthquake, the investigated sites could be possible to undergo crack settlement which can trigger massive sand boiling in the study area
The Correlation between Penetration Pressure Required to Install Pile Foundation and to Insert Bi-cones in Cone Penetration Test
Full text linkOne of the common methods used to install pile foundation is hydraulic jacked-in machine. In this method, a pile is pushed down into the ground up to the predetermined depth. The method has similar principle to that of Cone Penetration Test (CPT). This paper presents the correlation between the mobilize pressure required to install pile foundations and that required to push the bi-cones that attached at the tip of CPT rod. The results show that the penetration pressure required to install the pile into very soft clay layer is independent of pile diameter. The penetration pressure required to install the pile into soft to stiff clay layers depends on the pile diameter. The larger the diameter of piles, the smaller the penetration pressures required. The penetration pressure required to install the pile into stiff expansive clay layer beyond the depth of active zone can be predicted as high as the pressure calculated form CPT
Monitoring the Shear Fatigue Response of Reinforced Concrete Beams Subjected to Moving Loads using Digital Image Correlation
Full text linkA series of three reinforced concrete beams without shear reinforcement were tested to failure under a centre-span monotonic load, a centre-span pulsating load, and a stepwise-moving pulsating load. During each experiment, load-deflection response was continuously monitored and at several stages during the experiment, the load was briefly stopped for crack observations. In addition to this manual crack mapping, more detailed crack mappings were undertaken using the digital image correlation (DIC) technique, employing the open-source DIC software Ncorr. It was shown that while the three beams exhibited a similar mode of failure (i.e. shear), each beam displayed a rather distinctive overall behaviour, particularly with regard to the load-deflection response and the nature of crack initiation and propagation. Results from the DIC analysis are presented to provide direct evidence on the damage progression during the load cycles and discuss the reduced fatigue life exhibited by the beam subjected to stepwise-moving pulsating loa
Eco Drainage System for Surface Runoff Reduction in Indonesia
Full text linkSustainable urban drainage systems (SUDS) or eco-drainage system has been implemented in developed countries. The aims of the construction of the system are: to minimize surface runoff by capturing and temporarily retain it, to improve the quality of surface runoff, to infiltrate stormwater, to increase evapotranspiration, and to enhance landscape aesthetic value. Learning from the success of the implementation of SUDS in developed countries, the paper presents a model of eco-drainage system for residential area in Indonesia, which consists of rainwater harvesting system (RWHS) and retention ponds. A simulation of stormwater and surface runoff utilization is also presented. At 14,602.26 m2 bare land in Mojokerto Regency, East Java, which is transformed into residential area, the model of eco-drainage system could reduce surface runoff volume almost by 70%. It is recommended to adjust the dimension of rainwater storage tank and retention ponds in order to reduce more surface runoff volume
Permeation Resistance of Sawdust Ash Blended Cement Laterized Concrete
Full text linkThis paper compared the initial surface absorption of conventional concrete and laterized concrete containing Portland cement (PC) and sawdust ash (SDA). Laterized concrete was produced at laterite contents of 15 and 30% as partial replacement for sand and SDA contents of 10 and 20% as partial replacement for PC. Compressive strengths at 28 days and initial surface absorption after 10 minutes (ISA-10) at 28, 60 and 90 days were determined at the water/cement ratios of 0.35, 0.50 and 0.65 and assessed at equal 28-day strengths of 25-35 N/mm2. At equal water/cement ratios, compressive strength reduced and ISA-10 increased with increasing content of laterite and SDA. On the other hand, compressive strength and resistance to surface absorption of the blended cement laterized concretes increased with increasing curing age. At equal strengths, all the blended cement laterized concretes have better resistance to surface absorption than the conventional PC concrete
Analysis of Different Stripe Connectors for a Gabion Wall based on Woven Waste Tire Stripes
Full text linkIn this research, woven waste tire stripes are proposed as an alternative material to wire mesh to make a gabion wall. The performance of the waste tire stripe-based gabion wall is highly dependent on the strength of its stripe, where the stripe connector plays an important role. This research aims to inspect the behavior of different stripe connectors for the gabion wall. To achieve this, a physical model was built and employed to test the strength of the gabion wall. Various stripe connectors are used; adhesive rubber glue, one inch nail, and two mm wire. The strength capacity of the models was determined from the maximum stress before failure. The strength capacities of the models are 83.197, 59.426 and 62.397 kPa for the wire, nail, and glue connector, respectively. Hence, it can be inferred that the wire connector is the strongest of the three connectors
On the Derivation of Exact Solutions of a Tapered Cantilever Timoshenko Beam
Full text linkA tapered beam is a beam that has a linearly varying cross section. This paper presents an analytical derivation of the solutions to bending of a symmetric tapered cantilever Timoshenko beam subjected to a bending moment and a concentrated force at the free end and a uniformly-distributed load along the beam. The governing differential equations of the Timoshenko beam of a variable cross section are firstly derived from the principle of minimum potential energy. The differential equations are then solved to obtain the exact deflections and rotations along the beam. Formulas for computing the beam deflections and rotations at the free end are presented. Examples of application are given for the cases of a relatively slender beam and a deep beam. The present solutions can be useful for practical applications as well as for evaluating the accuracy of a numerical method
Study on Graphite Powder as Conductive Pigments for Impressed Current Cathodic Protection System using Carbon Fiber Reinforced Polymer Anode
Full text linkThe use of Carbon Fiber Reinforced Polymer (CFRP), for both strengthening material and anode for Impressed Current Cathodic Protection (ICCP) system, is being investigated. The focus of this study is to develop the epoxy that has good bond strength and electrical conductivity. Graphite powder is used as conductive pigments with percentage ranges from 7.5% to 17.5%. All specimens were partially submerged in 5% NaCl solution and induced with electrical current of 10 mA/m2 and 20 mA/m2 for 30 days. An average potential increase of 200 mV was recorded using half cell potential test. The application of 30 days ICCP up to current density of 20 mA/m2 did not affect the bond strength significantly and still complies with ACI recommendation. However, graphite content of more than 15% are found to be not workable and the bond strength is greatly reduced to less than 1 MPa This study concluded that the recommended graphite powder content shall be in the range of 10% to 15%
Performance Evaluation of Hot Mixture Asphalt Using Concentrated Rubber Latex, Rubber Compound and Synthetic Polymer as Modifier
Full text linkResearch on the utilization of natural rubber for Hot Mixture Asphalt as modifier has been widely carried out, and more intensively since 2016 due to the declining global natural rubber price. Further research conducted is the utilization of pre-vulcanized concentrated rubber latex and rubber compound added with antioxidants and treated through vulcanization process. This study experimentally evaluates the performance of Asphalt Concrete Wearing Course (ACWC) using natural rubber and synthetic polymer as modifier, compared to ACWC without modifier (only petroleum asphalt). The results show that the rubberized asphalt has higher index penetration value as well as higher elasticity compared to petroleum asphalt penetration grade 60, but lower than synthetic polymer modified asphalt. Similarly, the level of performance of rubberized asphalt mixtures, particularly resilient modulus, water resistance, deformation, and fatigue cracking, is between that of petroleum asphalt and synthetic polymer modified asphal