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1、International Standard 7844 0 4!i!i! 4 ,NTERNAT,ONAL ORGANIZATION FOR STANDARDIZATION*MEYHAPOHAR OPAHM3AUHR IlO CTAHAAPTH3Al.Wl.ORGANlSATlON INTERNATIONALE DE NORMALISATION Grooved vertical joints with connecting bars and concrete infill between large reinforced concrete panels - Laboratory mechanic
2、al tests - Effect of tangential loading Assemblages verticaux cranths B armatures de liaison et b b) the reinforcement connecting the two wall-panels shall be distributed uniformly over the total height of the storey and the vertical distance between reinforcing bars shall be small; cl the strength
3、of the concrete constituting the panels shall be at least equal to the strength of the infill concrete of the joint. This International Standard is applicable in the case of effects produced by tangential loading (shearing along the joint). The mechanical characteristics of vertical joints between r
4、ein- forced concrete panels which are taken into account in design calculations for bracing walls formed of large panels can be expressed by means of the relationship between tangential loading and the relative displacement of the panels linked by the joint concerned. 3 Principle Submission of test
5、pieces, comprising two side pieces of panels jointed together, to tangential loading. Noting the deformation of the test pieces and deterioration (cracking and failure) for different values of tangential loading. 1 Scope 4 Test apparatus This International Standard specifies a laboratory mechanical
6、method of test for the determination of the relationship be- tween tangential loading and relative displacement for certain types of vertical joints between large reinforced concrete panels subjected to tangential loading. The test apparatus shall be able - to ensure rigid fixing of the side pieces;
7、 - to allow slippage in the axis of the joint; Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/27/2007 22:00:31 MDTNo reproduction or networking permitted without license from IHS -,-,-
8、IS0 7944-1995 (E) - to avoid deformation of the installation up to failure of - in direction : f 5 x IO-3 rad relative to the the test piece; longitudinal axis of the joint; - to ensure application of the load in the direction of the - in geometric deviation in the middle of the joint : axis of the
9、joint. 2 mm. The accuracy required for the test apparatus (in the case of joints of strictly perfect dimensions) is as follows : The test apparatus may be designed to allow joints to be tested in the horizontal (see figure 1) or vertical (see figure 2) position. Axis along which the tangential stres
10、s is applied Side pieces Figure 1 - Example of test apparatus for testing in one direction in horizontal position A-A Groove - Projecting reinforcing bars Figure 2 - Example of device for testing in one direction in vertical position Copyright International Organization for Standardization Provided
11、by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/27/2007 22:00:31 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 7644-1965 (E) 5 Test pieces 5.1 Composition and dimensions A test piece consists of two side pieces represent
12、ing the sides of panels and the joint itself situated between these side pieces (see figure 31. Dimensions in millimefres /-Grooving J I . A-A Prefabricated side piece Joint Figure 3 - Shape and dimensions of test pieces The edge of each side piece, adjacent to the joint, reproduces the shape of the
13、 vertical edge of a panel with grooves, with optional flanges designed to close the joint and projecting re- inforcing bars. On the opposite side to the joint, the edge is designed to be fastened in the test apparatus. The reinforce- ment is thus quite dense in this area and traversing gaps pro- vid
14、e holes for the fixing devices of the test apparatus. The concrete on the side adjacent to the joints shall have the same strength and composition as that of the panels. NOTE - On the side to be fixed in the test apparatus, the cement con- tent of the concrete on the edges may be increased if necess
15、ary, so as to improve the strength and to avoid premature cracking near the fixing points. The thickness through the joint shall be identical to that of the actual joint in service; it can be adapted to the characteristics of the test apparatus at the fixing points The length of joint to be tested s
16、hall be approximately 2000mm. 5.2 Preparation The preparation of the test pieces shall reproduce site practice as closely as possible. The concrete used in the joint shall thus have a composition and workability as close as possible to those for use on site. For a research test, however, the possibi
17、lity of concreting with the joint in a horizontal position, and not systematically in the vertical position as on the site, can be allowed. For qualification tests, the preparation, including concreting, shall be identical to practice. 6 Procedure 6.1 Preliminary loosening Before testing, the joint
18、shall be loosened from one side piece. This can be done with small jacks acting perpendicularly to the side pieces and can be facilitated by using a demoulding agent,11 on the surfaces of the side pieces. This operation should be stopped when a crack is visible along the total con- tact surface betw
19、een the joint and one of the side pieces and the opening has a width of approximately 0,2 mm all along its length and on the two faces of the test pieces. 6.2 Determination 6.2.1 Static test in one direction The test shall be carried out by increasing the relative tangential displacement of the two
20、side pieces by applying a tangential load to the joint. Increase the load either step by step with chosen increments so that, taking into account the known or estimated limit state, this will be reached after about 10 increases, or, preferably, continuously (when the relative displacement is recorde
21、d con- tinuously). Even when this last procedure is used, several returns to zero loading are admissible during the test. Stop the test either when the joint shows heavy deterioration (failure of several projecting reinforcing bars, crushing of the concrete) or when the relative displacement of the
22、two edges reaches 20 mm. 1 I The use of a demoulding agent is recommended in the case of self-forming joints in order to eliminate the risk of rupture of the infill joint concrete. 3 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technic
23、al Standards 1/9972545001 Not for Resale, 04/27/2007 22:00:31 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 7844-1985 (El 6.2.2 Test with alternating tangent loads When it is necessary to know the behaviour of a joint on which alternating tangential loads are exerted,
24、 the test comprises suc- cessive stages during which the joint is submitted to alternating deformations, of contrary signs and the same absolute value, until a stable curve loop of load-deformation is obtained (see figure 4) or until 10 cycles have been carried out if a stable loop is not obtained.
25、T -Cycle 1 -Cycle 2 - Cycle 3 m Go Displacement, G Figure 4 - Example of tangential load-displacement diagram for an alternating shear test with imposed displacement The next phase is then carried out for a higher value of limit deformation and th,e test is terminated by a static test in one directi
26、on. The level of deformation to set is to be defined according to the problem under investigation (for example relatively small defor- mations for wind in service or large deformations in the case of seismic loading). 6.3 Test results 6.3.1 Maximum shear-resistance of the joint The maximum shear-res
27、istance of the joint is the maximum force registered during the test. It is expressed in newtons. 6.3.2 Deformation The deformation of the joint is the relative displacement of the side pieces parallel to the direction of the force. Such deforma- tions shall be measured preferably by means of a cont
28、inuous recordingl), mid-way along the test piece, on its two faces. The related displacements of the edges at the ends of the joint, and the increase in width of the joint at its two ends, shall also be measured. The deformation is expressed in millimetres. 7 Test report For each test carried out, t
29、he test report shall include the following information : a) the dimensions and shapes of the test piece and of the joint, and the shapes, dimensions and positions of connec- ting reinforcing bars, and of the reinforcement of the joint; b) the method of preparing the joint (horizontally or ver- tical
30、ly); c) a diagram of the test apparatus indicating, in the case of a horizontal test, the normal stress applied to the joint by the test apparatus; d) the programme for increasing the loading (rate of loading for a static test, imposed deformations for an alter- nating test); e) the deformations reg
31、istered parallel and perpendicular to the direction of loading, expressed as a function of the load; f) the formation of cracks and their development characterized by the position of the ends of cracks for dif- ferent values of the force applied; g) the maximum shear resistance of the joint per unit
32、 length of the junction. 1) The shape of the load-deformation curve gives important information on the behaviour of the joint, 4 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/27/2007 22:00:31 MDTNo reproduction or networking permitted without license from IHS -,-,-