80


 For specimens 3 and 4, a total of 21 LVDTs were used to measure the

displacements. The LVDTs were spaced at 1 ft intervals outside the constant moment

region and 9 in. intervals inside the constant moment region. The LVDTs were labeled

from north to south as Dl through D21 (see Fig. 5-9 and 5-10).

 Data from all instrumentation devices were recorded using a data acquisition

system at a rate of 1 Hz.

Material Properties

 To obtain the strength of the concrete used in piles tested, 6 x 12 in. concrete

cylinders were cast and tested in compression. The cylinders were tested on the same day

that the respective piles were tested. A total of 8 cylinders were tested using a cylinder

test machine. All cylinders were capped using sulfur as capping material. Table 5-2

contains the results from the cylinder tests.

Table 5-2. Results from cylinders tests
Pile Cylinder Peak Aver.
Specimen stress stress
 (ksi) (ksi)
 1&2 1 6.78 6.62
 2 6.46
 3 1 5.54 5.60
 2 5.63
 3 5.64
 4 1 6.08 6.15
 2 6.10
 3 6.28

 The physical and mechanical material properties for the flexural FRP reinforcement

were obtained from the manufacturer (Hughes 2002(a); Sika 2003) while the properties

for the CFRP grid were obtained through testing as described in Chapter 3. The

properties (diameter, cross-sectional area, tensile strength and modulus) of the FRP

materials are presented in Table 5-3.