Get this from a library! Building code requirements for concrete masonry structures: (ACI ). [ACI Committee ; American Concrete Institute.]. Get this from a library! Building code requirements for concrete masonry structures (ACI ) and commentary–ACI R [ACI Committee ]. Building code requirements for concrete masonry structures (ACI ) and commentary–(ACI R). [reported by ACI Committee ]. Detroit, Mich.
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Documents Flashcards Grammar checker. However, the structural significance of joint reinforcement in block masonry walls is not well established.
This pape r presents an experimental study of the strength of horizontally spanning joint reinforced block masonry walls under out-of-plane lateral loading.
Three wall panels were tested to determine the effect of amount of horizontal reinforcement on the wall cracking moment and flexural stength.
It is concluded that joint reinforcement does not influence the cracking load but the flexural strength, however, is increased depending on the type and spacing of the reinforcing steel. However, the structural significance of joint reinforcement in block masonry walls, particularly for seismic resistance, is not well established.
Full text of “ACI: Manual of Concrete Practice, Part 1”
There has been relatively few documented tests addressing The test the function of joint reinforcement in masonry walls. This wide range is attributed to variation in. Test data are scarce and conflicting. Ali available data are for vertically unreinforced walls, and as such Also, the does not represent reinforced masonry wall behavior.
A comprehensive experimental program was conducted at Orexel University to investigate the effects of amount and type of reinforcement, block size, bond type, grouting, and geometric parameters on the behavior of horizontally spanned joint reinforced walls using displacement control input.
Results of three walls tested to determine the effect of amount of joint reinforcement on wall flexural capacity are presented. The physical and mechanical properties of the 6 in. Cylindrical control specimens 2-in. The cylinders were air-cured alongside the companion walls and tested under axial compression at approximately the same age as the walls. The average compressive strength obtained for the mortar specimens was psi.
The average compressive strength of the grout was psi. Prefabricated truss type wire reinforcement from Dur-O-Wal, Inc.
Aci 531-79 pdf
Properties of the two types standard and extra heavy are listed in Table 2. The typical panel was made up of three full courses in addition to a half course at the bottom and at the top see Figure 1to represent a typical wall strip cut from center-of-block to center-of-block. The panel size was 32 in. Horizontal reinforcement was present in the three walls W1, W2, W3 in the following configurations.
The amount of horizontal reinforcement ranged from 0. The quantity of steel reinforcement used was based generally on the guidelines presented in the UBC 17 and the ACI 18which specify the minimum amount of wall 5331-79 in either the vertical or horizontal direction to be 0. Test specimens area of the wall.
In addition, the sum of the percentages of vertical and horizontal reinfo rcement is specified to be at least 0. Grouting was performed at 2-ft intervals at the hollow cores that contained the vertical reinforcement. Test Set-up and Instrument ation The walls were simply supported at the end and had a span of 74 in.
Two equal line loads, transverse to the span length, were applied to the face of each wall with the wall in a vertical position at the third points. Deflection and strain instrumentation were placed at specific locations on the walls. Figure 2 shows a schematic of the experimental set-up. A 55 kips MTS hydraulic actuator was operated under displacement control at a constant rate through a computer-based measurement and control system. Data acquisition was carried out on the the same computer system.
A displacement ramp was appl ied slowly and load was measured by the actuator precision load cell. The basic pattern of cracking was one of head joints separation and vertical Cracking splitting of the masonry units on the tension face. The cracks then propagated into the face-shell area in the same region. Once the crack pattern in the pure moment region had been established, load redistribution in the wall panel occurredas evidenced by the appearance of a set of vertical cracks just beyond the pure moment region.
Flexural Strength of Joint Reinforced Block Masonry Walls
The load at which these cracks in the shear span occurred was close to the failure load. Failure was preceeded by widening of cracks with no further addition to the crack pattern.
A loud snapping noise was heard shortly after the ultimate load was reached in the wall panels indicating the rupture of the joint reinforcement. Ultimate load increased when the amount of horizontal reinforcement in the wall increased, and joint reinforcement increased the flexural strength over walls without joint reinforcement. For walls without joint reinforcement the ultimate strength is assumed to be the cracking strength of the masonry assemblage. In comparing the ultimate load with the cracking load, it is found that joint reinforcement in every course increased the flexural strength by to percent depending on the type of reinforcement standard or extra heavy and joint reinforcement in every other course increased the flexural strength by just 64 percent Table 3.
The complexity of the crack pattern was found to be dependent on the 53-79 of the joint reinforcement. Walls with joint reinforcement in every course had a more developed crack pattern than walf with joint reinforcement in just every other course. A minimum amount of joint reinforcement is required to maintain a safe ratio between the cracking load and the ultimate load.
Joint reinforcement in every course adequately provides this ratio. Joint reinforcement in every other course increased the flexural strength 5317-9 about 64 percent while joint reinforcement in every course increased the flexural strength by to percent.
Therefore, the code minimum steel requirement in the horizontal direction 0. ECE to Drexel University is gratefully acknowledged.
Sabia and Company and is gratefully acknowledged. C and West, H. Collaboration Engineering Solutions and Products. Reinforcement Schedules Practice With Answers.