This work investigates the effect of calcium stearate (Ca(C18H35O2)2) on concrete shrinkage behaviors by using experimental testing. The test specimens are cubes with each dimension given as 100 × 100 × 285 mm for shrinkage tests and cylinders with 150 mm diameter and 300 mm height for compressive strength tests. The calcium stearate with fractions of 0, 0.1, 0.2, and 0.3% from the weight of cement are used in the tests. The results showed that the shrinkage occurred in amounts of 0.079, 0.062, 0.065, and 0.060 mm for the specimens containing calcium stearate of 0, 0.1, 0.2, and 0.3%, respectively. Moreover, we also perform shrinkage modelling to explore a possibility to incorporate the calcium stearate fraction into the standard concrete shrinkage model. There are three well-known shrinkage models used here, i.e., the Sakata, the Japan Standard and the Bazant-Baweja models, where only the latter one is capable to capture our experimental results very well for different fractions of calcium stearate.
This work investigated the performance of steel wire rope as an external strengthening for reinforced concrete beams with different end-anchor types. A study is conducted on reinforced concrete beams with the size of 100 mm x 150 mm x 1000 mm, consisting of 1 beam without strengthening (BTP); 1 beam strengthened with 2 steel wire ropes of diameter 6 mm with end-anchor type 1 (BPA1); and 1 beam strengthened with 2 steel wire ropes of diameter 6 mm with end-anchor type 2 (BPA2). It is found that the external strengthening of reinforced concrete beams using steel wire rope has the advantage of better serviceability due to its higher ductility than the beam without strengthening. The load-carrying capacity of reinforced concrete beams, which are externally strengthened with steel wire ropes, shows a significant increase of up to 60%. All specimens meet the minimum ductility requirements; in this case, the strengthening beams have other advantages, i.e. improved performance in preventing brittle failure. In this study, the increased stiffness is associated proportionately with the increased strength. This is supported by previous findings which suggest that the stiffness cannot be completely separated and independent of the strength. The failure in all specimens appeared in the same phases and all specimens experienced flexural failure. The ratios of end-anchor type 1 to end-anchor type 2 were close to 1 for all the parameters studied, which means that both types of end-anchor make an equally good contribution to the performance of steel wire rope.
Earthquakes 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.
Structural failure, which can be caused by design miscalculation or changes in the building’s function, can be dangerous if left untreated. Consequently, structural strengthening is done by providing steel plates, fiber-reinforced-polymer, or in the traditional way using bamboo fibers. In this study, a numerical calculation for bamboo strengthening using the FEM method is conducted. Bamboo strengthening was installed on concrete beams and attached using mortar. The analysis was carried out with ATENA software dealing with beam specimens, namely Control Beam (BC) and Bamboo-strengthened Beam using M13 and M20 mortar (BB13 and BB20). The materials used are CC3DNonLinCementitious2 and CCD3DBiLinearSteelVonMises for concrete and bamboo, respectively. The concrete and mortar use the fracture concept of a uniaxial stress-strain law and the constitutive model of the bamboo is based on a linear stress-strain law. The results of comparing the numerical and experimental results for the load-carrying capacity ratio are 0.96, 0.90, 0.77 for BC, BB13, and BB20, respectively. The crack pattern of the specimens shows that collapse is by flexural cracking starting from the mid-span. This is in accordance with previous laboratory results. In conclusion, the analyses using ATENA program and experimental methods show the appropriate results.
A need to predict the seismic vulnerability of current buildings has led to a heightened interest in study that deals with seismic vulnerability assessment methods. The easiest and fastest method, known as a walk-down survey or a street survey, involves just the superficial information accumulated during a short inspection of a building. This paper picks a fairly new seven-story academic building made of reinforced concrete (RC) located at the Jenderal Soedriman University in Purwokerto, Indonesia, which was designed in 2015 using construction details illustrative of that exact period, for FEMA 310 Tier 1 assessment in the context of Performance-Based Earthquake Engineering (PBEE). Mandatory checklists as a role of the region of seismicity and the building’s level of performance are done. The outcomes after a procedure projected the building in the case-study demonstrated a range of possible flaws and seismic vulnerability. Therefore, detailed comprehensive evaluation is intensely endorsed.
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