Temporary propping

In this relatively young field of research, the experimental and theoretical results lend themselves better to associations and trends analysis than to quantitative correlations and theoretical predictions. Empirical structure-property relations should be regarded as temporary props that can be useful, but should be modified if serious exceptions are found. They should be regarded as a stage in the evolution from ignorance to empiricism, and then into knowledge and reliable theory, and should be supplanted when better ideas arrive. 

A further major consideration in the repair of structural concrete elements is the decision as to whether to relieve the element of load whilst the repair process is being performed. If the application of live or imposed load is prohibited during the process of concrete removal but dead load is not temporarily resisted by propping then there will be a redistribution of dead load stresses within the residual section. Further, the patch repair material will not subsequently contribute to the support of dead load. Alternatively, if both dead and live loads are supported by temporary props whilst the repair is carried out then the reapplication of dead load will result in subsequent creep of the repair material under the sustained stress, whilst any cyclic live loads will induce fatigue loading on the repaired section. A third possibility, for example in the case of columns... 

During retrofitting activities, due to the demolition works on the structure, temporary propping works are required. This stage of the works is the riskiest, as unexpected collapses and casualties may occur. 

The designer shall be responsible for performing periodic structural observation of the retrofitting works at significant stages of construction like temporary propping, demolitions, reinforcements, details, etc. This procedure should be in addition to any special inspection and testing. 

Teams of roof inspectors followed the clearing gangs. As they encountered areas of bad roof they either inserted temporary wooden props, or where necessary brought down all the loose stone to reveal the more secure stratum above. At first men more familiar with colliery techniques worked as safety men, but following an early fatal accident only Bath stone quarrymen were so employed. The accident occurred on Saturday... 

The Cementation Co, which was already working on the ventilation shafts for the main area, was also contracted to drive two new inclined access shafts in the temporary districts. Construction of the perimeter walls was well in hand by the start of the new year, but as debris was removed from the north-west comer of K District a number of serious roof collapses occurred, so all further work was abandoned in that area, resulting in the loss of 20% of the planned storage capacity. A limited amount of steel-work was put in place to support the roof, but as K area was classified as only temporary storage extensive use was made of creosoted wooden props, over 520 of which were erected. By March heavy construction in K area was complete and the slope shaft lined with concrete. It was decided to leave the floor with a consolidated Bath... 

For temporary or contract workers, safety professionals should be aware that the worker s status is often determined by the terms and conditions agreed upon in a written contract. Although the worker may be working within your operations, the worker may actually be an employee of another company or entity provided to your company to perform specific tasks under a written contract. Although there may be many different variations of the contract terms and conditions, safety professionals should be cognizant to ensure that contract workers are properly trained, prop-... 

Requirements for any temporary works, temporary bracing and propping should be given in the Erection Method Statement (see 6.1.2). The stage when temporary bracings/supports can be removed, and the erected structure is able to accept all loadings, including wind, must be defined in the Method Statement. 

---