Structural testing testing steel truss under static load experiment purpose and requirement for testing steel truss

HO CHI MINH CITY UNIVERSITY OF TECHNOLOGY OFFICE FOR INTERNATIONAL STUDY PROGRAMS STRUCTURAL TESTING Student : Do Tan Kiet ID number : 1852490 Adviser : Assoc Prof Ho Duc Duy Subject code : CI4011 Ho Chi Minh City, November 2022 PREFACE Structural inspection course has played a big role for most students majoring in civil engineering including those who have graduated from university and take it as a guide The course sets out essential design theory and illustrates practical applications in our profession Topics have broadened our horizons of some of the widely used experiments in civil engineering, but they have also given us broad access to learning and self-improvement Especially, after participating in the structural experiment course, we have learned and made great progress in the necessary knowledge such as (i) equipment and measuring instruments used in experimental survey, (ii) testing to determine the mechanical characteristics of concrete and steel, (iii) evaluating the performance of the structure by loading test and (iv) verifying the quality of the work Overall, I would like to express my great appreciation to Assoc GS Ho Duc Duy about the valuable knowledge and valuable advice that he has taught and shared during this course Signature Contents EXPERIMENT 1: TESTING STEEL TRUSS UNDER STATIC LOAD 1.1 Experiment purpose and requirement for testing steel truss: 1.1.1 Experiment: 1.1.2 Requirement for testing steel truss: 1.2 Experimental diagram: 1.3 Apparatus: .7 1.3.1 Hydraulic pump: 1.3.2 Strain measurement equipment: .8 1.3.3 Dial indicator: 10 1.3.4 Load cell: .11 1.4 Procedure: 11 1.4.1 Preparation: 11 1.4.2 Testing procedure: .11 1.5 Testing result: 12 1.6 Calculated data: 12 1.7 Theoretical calculation of stress, strain, deflection: .13 1.7.1 1.8 Modeling the steel truss using SAP2000: 13 Result and discussing: 17 1.8.1 Comparison between testing method and SAP modelling method: 17 1.8.2 Discuss the result between testing and SAP modelling method: 23 1.8.2.1 : Comment on chart result: 23 1.8.2.2 Cause of differences: .23 EXPERIMENT 2: REINFORCED CONCRETE BEAM 25 2.1 Experimental purpose: .25 2.2 Experimental diagram: 25 2.3 Apparatus: 26 2.4 Procedure: 27 2.4.1 Preparation: 27 2.4.2 Testing procedure: .28 2.5 Testing result: 28 2.6 Calculated data: 29 2.6 Theoretical calculation of stress, strain, deflection: 30 2.6.1 Reinforcement concrete theory: 30 2.6.1.1: Initial data: .30 2.6.1.2: Deflection: 31 STRUCTURAL TESTING SUBJECT QUESTION .36 LIST OF FIGURES Figure Steel truss diagram Figure Steel truss experiment under static load Figure Hydraulic pump Figure Switch and Balance Unit SB10 Figure Vishey measurement P3500 Figure Strain gage .10 Figure Dial indicator 10 Figure Steel truss 10 Figure Load cell 11 Figure 10 Axial force of the steel truss for case F1=1.5kN 16 Figure 11 Deflection node I 18 Figure 12 Deflection Node II 19 Figure 13 Strain gage 20 Figure 14 Strain gage 21 Figure 15 Strain gage 21 Figure 16 Strain gage 21 Figure 17 Strain gage 22 Figure 18 Strain gage 22 Figure 19 Strain gage 22 Figure 20 Concrete beam diagram 25 Figure 21 Reinforced concrete beam testing at the laboratory 26 Figure 22 Hydraulic jack and load watch for applying and controlling load 27 Figure 23 Switch and Balance Unit SB0 and P3500 27 Figure 24 General dimension for all 30 Figure 25 Loading action on beam according to the first level of load (i=1) 32 Figure 26 Moment distribution of beam according to the first level of load (i = 1) 32 Figure 27 Case of loading RC beam 34 LIST OF TABLES Table Result of deflection and strain for the 1st experimental testing 12 Table Result of deflection and strain for the 2nd experimental testing .12 Table Calculated result of deflection and strain for the 1st experimental testing 13 Table Calculated result of deflection and strain for the 2nd experimental testing 13 Table Average the calculated result of deflection and strain for the experimental testing 13 Table Summarize the result of deflection and axial force from ETABS 17 Table Summarize the result of deflection and strain value according to elastic theory .17 Table Comparison the deflection result between testing method and SAP2000 .18 Table Comparison the strain result between testing method and SAP 19 Table 10 Result of deflection and strain for the 1st experimental testing 29 Table 11 Result of deflection and strain for the 2nd experimental testing 29 Table 12 Calculated result of deflection and strain for the 1st experimental testing 29 Table 13 Calculated result of deflection and strain for the 2nd experimental testing 30 Table 14 Average the calculated result of deflection and strain for the experimental testing 30 Table 15 Summaries the calculation of stiffness factor  33 EXPERIMENT 1: TESTING STEEL TRUSS UNDER STATIC LOAD 1.1 Experiment purpose and requirement for testing steel truss: 1.1.1 Experiment: Become familiar with the method of testing a bar structure, know how to use measuring devices to determine experimentally stress and displacement Determine the stress in the truss rod, deflection, displacement of the truss From there, compare the results between theory and experiment when considering: • Stress (expressed through strain) of truss rod • Deflection and displacement at some positions on the steel truss 1.1.2 Requirement for testing steel truss: • Measure strain  at some representative bars in the array Stress  and internal force N in truss bars • Measure deflection  at some positions on the truss • Compare experimental and theoretical results 1.2 Experimental diagram: Figure Steel truss diagram     The steel truss has trapezoid shape, including spans, each span has 0.5m in height and 1m in length Structure of truss steel bars as in the following table: Piston diameter: 5.6 cm Gusset plate thickness: 4-5mm Chord and side web Interior web Specifications Area(A) (cm2) X-axial moment of inertia Jx (cm4) Modulus E (N/cm2) 2L40x40x5 7.58 5.4 2.1x107 2L40x40x4 4.54 1.8 2.1x107 1.3 Apparatus: 3 Figure Steel truss experiment under static load with Hydraulic pump Strain measurement equipment Dial indicator Strain gage 1.3.1 Hydraulic pump: Scope:   To create stress (daN/cm2) through the load cell acting on the fully rigid beam, then transfer the reaction force to the sides of the steel truss as showed in the above figure The load acting on the sides of the truss is calculated as follow: ( F= v × where: v: Pressure value that read on gauge (daN/cm2) ) π d2 ÷2 d: Diameter of the piston (mm) Figure Hydraulic pump   The testing uses the 20 tons’ hydraulic pump with the piston diameter (d = 56mm) The process of loading and unloading of the hydraulic pump equipment should be processed by each loading level After unloading the pressure to zero, wait about 10 minutes to continue to operate 1.3.2 Strain measurement equipment: Figure Switch and Balance Unit SB10  • Switch and Balance Unit SB10: Including 10 channels plus open position that allow to measure up to 10 strain gages at the same time The equipment consists a switch button to determine each value of strain gages The channel switch of the SB-10 has an open position to allow the use of additional SB-10’s with a single P-3500 strain indicator • The combination of a P-3500 and SB-10 allows the operator to intermix, in a single 10- channel system, quarter, half and full bridge circuits  Vishay measurement P3500: • The model P-3500 Vishay measurement is a portable, batterypowered instrument with unique features for use in stress analysis testing and for use with strain gauge-based transducer • The value extracted from the electronic meter of the device showed the negative value is for the strain gage location that are under compression, and positive value for tensioning  Strain gage:  Based on tensest effect, when the conductor is mechanically deformed, the resistance also changes The value extracted from the Vishay measurement based on the following formula: ε g= ∆ R g / Rg GF Figure Strain gage 1.3.3 Dial indicator: Small displacement gauges:   The type of gauge used in the experiment is an electronic clock That scale is mm Minimum division 0.01mm In the experiment, install clocks to measure the deflection of button positions in the steel frame Corresponding to the increasing or decreasing displacement of each node position that we set the clock up or down Figure Dial indicator Figure Steel truss 1.3.4 Load cell:   An electronic weighing load cell are used to install electronic scales These load cells are usually made of allow steel with various shapes, loads and sizes This equipment is widely used in many industrial and civil fields The load cell is connected to the hydraulic pump, then the hydraulic pump will transfer pressure to the load cell, through the steel ball and then acting to the structure Figure Load cell 1.4 Procedure: 1.4.1 Preparation: The experiment was performed in a group of 15 members The tasks of each member are as follow: +) Duyen: Setup and read switch and Balance Unit SB10 +) Minh Duy: Set up and read data from Vishay measurement P3500 +) Chi Huy: Adjusting the hydraulic pump into the specific pressure level that the instructor has already required +) Phuc Dat: Set up and checking the dial micrometer value +) Dai Duong: Set up and checking the dial micrometer value +) Others on the team were responsible for assisting with the lighting, taking pictures of the equipment, and checking the metrics 1.4.2 Testing procedure: Step 1: Check and re-measure the truss bars with a steel ruler and caliper Step 2: Arrangement of deflection and strain gauges (already arranged in advance) Adjust the deflection gauges to Place the deflection gauges in the correct position to be measured and always touch the steel frame when the load is increased Step 3: Control the hydraulic jack from to 1.5-3-4.5-6 kN by continuously pushing the hydraulic jack below the truss 10 ... 33 EXPERIMENT 1: TESTING STEEL TRUSS UNDER STATIC LOAD 1.1 Experiment purpose and requirement for testing steel truss: 1.1.1 Experiment: Become familiar with the method of testing a bar... knowledge and valuable advice that he has taught and shared during this course Signature Contents EXPERIMENT 1: TESTING STEEL TRUSS UNDER STATIC LOAD 1.1 Experiment purpose and requirement for testing. .. Deflection: 31 STRUCTURAL TESTING SUBJECT QUESTION .36 LIST OF FIGURES Figure Steel truss diagram Figure Steel truss experiment under static load Figure