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 Test Loading
3.
The test loading was performed in accordance with part 6, Chapter 20
"Strength Evaluation of Existing Structures" of the American Concrete
Institute Building Code (ACI 318-77). At section 20.4.3, the Code states
"That portion of the structure selected for loading shall be subject to a
total load, including dead loads already acting, equivalent to 0.85 (1.4 D +
1.7 L) where D = Dead Load and L = Live Load.
(1) Method of Loading
Falsework was used for safety precautions (Fig. 21). A schematic of the
method of loading is shown in Fig. 22 and the various increments in Fig.
23. Deflections were measured by using deflection gages capable of
measuring from .001" to 1.0". The deflection measurements are as follows:
Deflection in Inches
Increment
.0012
1
.003
2
.0036
3
.084
Full Load
After 36 Hours
.O996
.0072
Unloaded
Total predicted deflection was .095" which was greater than the deflection
under full load. Creep was observed 36 hours after completion of testing.
The deflection differential was 0.0156" within accepted limits. Almost full
recovery of the outlooker demonstrated that no yield occurred in the main
tensile reinforcement. Visual inspection showed no shear cracks or diagonal
tension cracks during testing. Few hairline cracks in the tension area
appeared during maximum loading which were closed totally during the rebound
period.
Solution:
Anchoring Studs.
1.
Symptom: The separation of anchoring studs from the concrete shown in
Enclosure 2 is evidence of lack of sufficient embedment or concrete cover.
Provide additional embedment and concrete cover.
Remedy:
Bars at the end of outlooker (Nose Bars).
2.
Lack of nose bars.
Symptom:
Add nose bars.
Remedy:
Beams which will not be restored.
3.
Hairy shear cracks.
Symptom:
Seal cracks with mortar to prevent moisture and corrosion of steel.
Remedy:
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