Determination of conditions for loss of bearing capacity of underground ammonia pipelines based on the monitoring data and flexible search algorithms

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Efficiency Analysis of Foundation System

The increasing number of residents in South Tangerang has an impact on increasing the need for lower housing. The development of vertical housing with the market name of flats, apartments and is the most effective anticipatory solution to overcome land prices which result in market limitations, especially for the upper middle class. This 32-storey apartment project uses a combined foundation system between drill pile foundation & raft foundation. With the combination of these two very massive systems, of course, it will have a very expensive cost to implement and take a long time to complete. In order to avoid cost overruns, the foundation design must look at the possibilities. To determine the efficiency of the combined system foundation design between pile bored foundation & raft foundation, the researchers analyzed the value of the bearing capacity and also the settlement that occurred in the existing foundation using the Poulos method, the equivalent Raft method and the Vesic method. From the results of the study, it was found that the contribution of the pile foundation bearing capacity was 24.10%. the placement of the raft foundation is 75.90% and the settlement analysis using the Poulos 8.95cm method, the 12.41cm Equivalent Raft method and the Vesic 12.1cm method, these three results are close to the maximum settlement limit.

Experimental investigation on behavior of splicing glass fiber–reinforced polymer-concrete–steel double-skin tubular columns under axial compression

Splicing glass fiber–reinforced polymer (GFRP)-concrete–steel double-skin tubular column (DSTC) is to set connection component at the joint of two or more separated GFRP tubes, and then pour concrete in the double-tube interlayer to form a continuous composite member. In this paper, the splicing DSTC composite members based on steel bar connection were designed and tested under axial compression to determine its mechanical performance. The main parameters include the connection steel ratio, the hollow ratio, and the thickness of GFRP tube. The results show that the GFRP tube presents apparent constraint effect on the concrete at about 60% of the ultimate load. The failure of splicing specimen occurred in the non-splicing section at a certain distance from the splice joint, and the stirrups at the splice joint provide effective constraint effect on the internal concrete. The proposed DSTC splicing method based on steel cage connection can satisfy the strength requirements of splice joint. Nevertheless, the increase of axial steel bar ratio cannot improve the bearing capacity of the splicing column, and the steel ratio of 2.44% is suggested for the splice joint of DSTCs under axial compression. The axial bearing capacity of splicing DSTCs significantly increases with the increase of GFRP tube thickness, but the amount of stirrups should be increased properly when a larger tube thickness is used. Two models were selected to calculate the bearing capacity of splicing members and it is found that Yu’s model is more accurate in predicting splicing DSTCs.

Bubbled Roller Compacted Concrete Dam: an idea of a hollow dam

Roller compacted concrete is widely known for its relatively low cost and short construction time. RCC gravity dams require high foundation (rock) bearing capacity. Research has been carried out which proposes to rationalise the amount of material in the dam by creating inner voids, in the shape of bubbles. As a key requirement, the introduced bubbles should not affect the dam stability and safety. The bubbles will reduce the self-weight of the dam and minimise the required rock bearing capacity. A system of pipes connecting the bubbles ensures drainage of the bubbles. The proposed dam would save about 12% of the required concrete volume. Different construction methods were studied and the best alternative is the use of precast hollow boxes. This decreases RCC placement in the dam by 32.5%. The objective is to speed the construction process and minimise the risk of the heat of hydration.