Assessment 2 T1 2022.pdf - CVEN9809 Assessment 2 T1/2022...

CVEN9809 Assessment 2 T1/2022 Due date: April 5
QUESTION 1: (60 marks)
A strut-and-tie model developed for a deep corbel under dead (permanent) load P
G =
300 kN and Live
(imposed) load P
Q
=240 kN is shown in Figure-1 . The dead and live loads are point loads applied at
point C . The dead and live loads are resultant of distributed loads in residential building. The self-
weight of the corbel was included in P
G
. Assume that all reinforcing steel bars to be used are normal
ductility with yield strength of f
sy
= 500 MPa. In the strut-&-tie model, strut BC is bottle-shaped. The
corbel is part of a residential building, and a minor degree of crack control is required.
(a) Determine the internal forces in the struts AB (prismatic) and BC (bottle-shaped) and ties AC
and AD for the most critical ultimate strength limit state loading conditions. Note: Only
consider the Dead and Live loads . Two load combinations must be considered. (10 marks)
(b) Determine the number of N24 required for the ties AC and AD under ultimate strength limit
state loading conditions. Take f
sy
= 500 MPa. (5 marks)
(c) Determine the minimum required concrete compressive strength
c
f
′
, if the thickness of the
corbel and column is taken b = 250 mm. Assume that the struts have no compressive bars. Note:
Capacity of the struts AB and BC and nodes should be checked under ultimate limit state
conditions . (20 marks)
(d) Determine the spacing ( s
1
and s
2
) of N12 steel bars in the horizonal and vertical direction to
prevent bursting of the bottle shaped strut BC according to serviceability and strength design
requirements of AS3600-2018. Assume that the corbel thickness b = 250 mm and the corbel is
reinforced by two layers of orthogonal N12 steel mesh with reinforcing proportion in x