Direct Loading Tests Research Articles

ANALISA KOMPARASI DAYA DUKUNG PONDASI BORED PILE SECARA ANALISTIS TERHADAP HASIL LOADING TEST STUDI KASUS PROYEK PEMBANGUNAN REZ HOTEL

Foundation failure and other factors that can cause bearing capacity to be incompatible when in the field. This is one of the factors that encourage direct loading tests in the field. Main objective of this study is to s to calculate and compare the ultimate bearing capacity of drilled pile after implementation with ultimate bearing capacity at the time of planning. SPT results were calculated using the Aoki Velosso method, the Decourt method, and the Reese & Wright method. Based on the calculation of the carrying capacity that has been carried out, there are differences in results, both due to the use of the method and the location of the point being reviewed. Based on the SPT data obtained from the calculation results of each Aoki Velosso method for TP-1/BP.48 the value of Qu = 783,933 tons while for TP-3/BP.78 the value of Qu = 1301,239, the Decont method for TP-1/BP.48 values Qu = 2593.098 tons while for TP-3/BP.78 the value of Qu = 2091.817, the Reese & Wright method for TP-1/BP.48 the value of Qu = 401.030ton while for TP-3/BP.78 the value of Qu = 334.022 and the results The loading test of the two test piles is TP-1/BP.48 Qu = 256 tons and TP-3/BP.78 Qu = 257 tons. Based on the calculation results, it can be seen that the efficient method used is the Reese & Wright method because the results of the calculation method are the smallest results, this is necessary to maintain building safety.

Comparison of new LCR and ordinary prestressed concrete railway sleepers with LUR tests

Rail operations today have become more difficult due to increasing operating speeds and decreasing maintenance times. New developed, laminated carbon fiber reinforced polyurethane (L-CFRPU) reinforced concrete railway sleepers (LCR) have the potential to show longer service life in this demanding condition. In this study, a large number of specimens with various reinforcement variations were produced, and improved incremental loading–unloading-reloading (LUR) tests and common one-stage static loading (direct loading) tests were performed. Sleeper deformations, first crack formation loads, and permanent crack width measurements were also recorded during the tests. It is revealed that there are significant differences in peak load capacity, modulus of elasticity, and maximum deformation values between the results of the direct-loading tests and the LUR tests. According to the results, the new LCR sleepers have met the static capacity requirements of standards and also show fewer vertical plastic deformations, which are very important for high-speed railways. Among the samples, sleepers with L-CFRPU surface sanded, and with more spread of L-CFRPU in the concrete section showed better performance than the other sleepers.

Comparison of out-of-plane tensile moduli of CFRP laminates obtained by 3-point bending and direct loading tests

The out-of-plane tensile modulus of laminated carbon fiber reinforced plastics (CFRPs) was evaluated through 3-point bending tests using laminated UD-CFRP and quasi-isotropic (QI) CFRP samples with out-of-plane span directions. Direct loading tests of QI-CFRP samples were performed for comparison. It was shown that the bending modulus measured for a UD-CFRP specimen with L/t>25 is consistent with the tensile modulus if the bending modulus is less than 15GPa. An analytical description of the out-of-plane modulus of thin QI-CFRP samples was derived by modifying the three-dimensional laminate theory and introducing conditions similar to plane-stress. Subsequently, it was demonstrated that this modified out-of-plane modulus is the lower bound of the apparent bending moduli and that the one predicted by the three-dimensional laminate theory is the upper bound. Finally, it was demonstrated that the 3-point bending test method is more practical than a direct loading test when comparing both methods.

Comparison of out-of-plane tensile strengths of aligned CFRP obtained by 3-point bending and direct loading tests

In order to propose a simple and effective test method for the out-of-plane tensile strength of laminated carbon fiber reinforced plastics (CFRPs), 3-point bending tests using an aligned CFRP with the span direction coinciding with through-the-thickness direction were performed, and the results were compared with those obtained by the direct loading test proposed by the authors. Weibull statistics were applied to evaluate the size and stress distribution effects on both results. The out-of-plane tensile strengths obtained by both tests were found to be consistent. Thus the 3-point bending test was recommended as a standard test method to evaluate the out-of-plane tensile strength of CFRPs from the perspectives of ease of preparation of the specimen and the simple procedure to derive the strength.

Influence of loading-unloading treatment at room temperature on critical current of bronze-processed Nb 3Sn superconducting composites

Influence of loading-unloading treatment at room temperature on critical current of bronze-processed multifilamentary Nb 3Sn superconducting composite materials were studied. The axial residual strain in Nb,Sn was predicted by the proposed simple model. In the present specimens with low volume fraction of Nb 3Sn and high tin concentration in bronze, the residual strain in Nb 3Sn at 4.2 K, which was minus (−0.65%) in the annealed condition, was raised to plus (up to +0.32%) by this treatment. According to this change in residual strain, the critical current increased but then decreased with increasing applied stress at room temperature. The variation of critical current as a function of strain in Nb 3Sn due to this treatment was considered to be essentially the same as that due to direct loading at 4.2 K, which has been reported until now. It was found that the upper critical field and critical current of tested specimens can be scaled out by the law having been found in direct loading test at 4.2 K.