Full Scale Load Testing BPEX Project, Maptaphut Rayong

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2 LOAD TESTING PROGRAM2.1 TESTING PROTOCOL AND ACCEPTANCE CRITERIAThe procedure used for conducting load tests in concrete structures is described inchapter 20 of ACI 318 “Strength Evaluation of Existing Structures.” In summary, thechapter provides guidance on establishing the magnitude of the test load andevaluating of the results. It suggests that the test load be placed in stages, toeliminate impact and to allow the structure some time to deform under the load.After recording of the base reading (which shall be taken not more than 1 hr beforeloading), the load is typically applied in increments of 25% of the full test load (fouror more equal increments approximately) every hour. The deflections are measuredafter each load increment and after the full test load is in place. At the end of a 24 hrholding period, another set of deflection measurements are taken and the test loadis then removed. The deflection recovery or the residual deflection is measured aftera 24‐hour rest period. This is to permit at least some time dependent effects such ascreep and load redistribution within the structural system to occur and if they aresignificant to become apparent and measurable.According to ACI 318‐08, the total test load should not be less than1.15D+1.5L‐1.0D = 0.15D+1.5Lwhere D is the dead load and L is the live load on the structure<strong>Load</strong> tests for both uniform and concentrated loading can be performed. The testcan be conducted using piled up sandbags, steel bundles or concrete blocks.ACI 318 deems the test satisfactory if the structure does not show any evidence offailure (spalling and crushing of compression zone concrete) and if the measureddeflections of the member satisfy any of the following two limitsΔΔ2≤ l t/ 20,000h≤ Δ / 4maxrmaxwhere Δmaxis the maximum displacement measured during application of the testload relative to the initial position no more than 1 hour prior to the application ofthe test load, l tis the member’s span length under the test load and h is its overallthickness or height of the member being tested. Δr is the residual deflection‐ themaximum displacement measured 24 hour after removal of the test load relative tothe initial position.If the test fails to meet these two criteria, the code allows a repetition of the test,which can be performed not earlier than 72 hr after the initial load of the first test is2
emoved. The second test may be considered acceptable if the maximum residualdeflection does not exceed 20 percent of the maximum deflection during the secondtest, measured from the level at the beginning of the second test.Any cracking that occurs during load testing is a cause for concern and should beinvestigated. Cracks that indicate an imminent shear failure of the tested membersare of special importance and should be viewed with alarm. The code specificallymentioned long cracks (those with a horizontal projection longer than the depth ofthe member) occurring in regions where transverse reinforcement is absent.Similarly, horizontal or short inclined cracks in the regions of probable anchorage orlap splices of reinforcement should be investigated, because such cracks could beprecursors of brittle failure.2.2 LOAD TESTING PROGRAMA number of items were considered prior to the load test, they included test loadconfiguration, the means by which the test load would be applied, the procedure forapplication of the test load, and the duration of application of the test load. Theseitems are discussed in this report.2.2.1 TEST LOAD CONFIGURATIONA site meeting was arranged to review the field conditions prior to the load test. Thefirst task facing engineers and technicians conducting a field investigation was todetermine the type of structure and to check it against any information availabledrawings. During a preliminary walk‐through, the team visited an area above andbelow the tested member. There, the dimensions of the beam cross sectionmeasured of 500x900 mm. The beam spanned 9 m on center carrying the slab,supported by reinforced concrete columns. The slab thickness was estimated as 150mm. Based on measurements conducted, the concrete beam seemed to be in goodcondition, with little damage observed. Figure 1 shows the typical PE and PF views ofthe test structure. Figure 2 shows the condition of the RG4 beam investigated.A series of in‐situ non‐destructive tests was performed with the purpose ofinvestigating 28‐day concrete compressive strength. Figure 3 shows the reboundhammer test and Table 1 summarizes the test result. Based on the test, the averagecompressive strength was above the specified compressive strength of 280 kg/cm 2as specified in the drawing.3
Page 1 and 2: Full‐Scale Load Testing ofSelecte
Page 3 and 4: EXECUTIVE SUMMARYThis report provid
Page 5 and 6: LIST OF FIGURESFigure 1. Test struc
Page 7: Full‐Scale Load Testing of Select
Page 11 and 12: TABLE 1. COMPRESSIVE STRENGTH FROM
Page 13 and 14: FIGURE 5. STEEL LOAD PLATFORMFIGURE
Page 15 and 16: 3 INSTRUMENTATIONS AND MEASUREMENTS
Page 17 and 18: 3.2 CRACK MONITORINGA survey telesc
Page 19 and 20: The predicted deflection at various
Page 21 and 22: 5 LOAD TESTING RESULTS5.1 DEFLECTIO
Page 23 and 24: 5.2 DAMAGESDuring the testing, exis
Page 25 and 26: FIGURE 18. INTERFACE SHEAR CRACK6 C
Page 27 and 28: 9 APPENDIX: MOMENT CURVATURE ANALYS
Page 29 and 30: 318.1116.1202C cAll dimension are i

Full Scale Load Testing BPEX Project, Maptaphut Rayong

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