Abstract:
A total of fourteen brick aggregate reinforced concrete
deep beams have been tested in this study in order to investigate
the effect of the flexural and the horizontal shear reinforcements
on the strength of such beams. The test beams were single span and
simply support8d type. The beams were divided into two series
according to "heir span to depth ratio (LID = 1 and 2). The
first beam of each series was designed and detailed as per the
recommendations of ACI Building Code (ACI 318-89). In the other
six beams of each series, the amount of either the flexural or
the horizontal web reinforcement or both were increased in
relation to those of first beam of the corresponding series.
The nominal cross section of the first series of test
beams was 6"x21" and that of the second series was 6"x12". The
effestive span lengths for two different series of beams were 21"
and 24" respectively.
The test beams were subjected to uniformly distributed
loads. The effects of the variations of different horizontal
reinforcements (flexural and web reinforcements) and span to depth
ratio on the cracking load, ultimate load, crack pattern, and the
mode of failure were investigated.
It was observed in the study that the amount of both the
flexural and the horizontal web reinforcements influenced to some
extentthe diagonal cracking load and the ultimate load capacity of
test beams. It was also found that the change in the amount of
either the flexural or the horizontal web reinforcement
alonecould not bring about a significant change in the load
carrying capacity of test beams. Certain modifications are suggested in five of the several
available formulas (e.g. ACI 318-89 Singh, Ray and Reddy
Ramakrishnan and Ananthanarayana ; Selvam and Kuruvilla ; and Mau
and Hsu) in order to compute the ultimate load of deep reinforced
brick aggregate concrete beams. It was shown that all of the five
formulas with the suggested changes can be used efficiently to
estimate the ultimate load capacity of deep beams.
