for the tube beam was approximately 5% lower than the crushing strain calculated for the

control beam.


0 1000


 0

S-2

S-4
C
S-6

S-8

 -10


Strain (microstrains)
 2000


Figure 4-17. Compressive strain profile for control beam

Table 4-3. Experimentally calculated top compressive strains
Beam Load (kips) Experimentally
 calculated top
 strain (ps)
 Control 21.9 333
 43.7 681
 65.6 1048
 87.3 1436
 109.0 1883
 148.0 3167
 Tube 22.4 421
 45.4 770
 67.4 1127
 89.2 1481
 110.2 1891
 152.3 3010

 Design codes usually assume a concrete crushing strain of 3000 p, (ACI

Committee 318), which agrees well with the crushing strains calculated from the

experimental data. Typically, concrete crushing strains vary from 3000 to 4000 p, (Nawy

2005; Hasoun and Al-Manaseer 2005; Hassoun 2002; MacGregor 1997). Lower strength

concretes (less than 5000 psi) are typically more ductile and have higher crushing strains


 \ /+ +P= 21.9 kips
 SP = 43.7 kips
 o P = 65.6 kips
/ J x P = 87.3 kips
 OP = 109.0 kips
 AP = 148.0 kips