BUILDING TECHNOLOGY-FRAMED STRUCTURES

Building Technology-Framed Structures

Building Technology-Framed Structures

Grade parkings, as shown on the subdivisions approved lot grading plan, must be referenced on the site plan at the lot corners. Additional grade parkings must be shown at the side property line opposite the corners of the building envelope. Where necessary, these grades shall be interpolated from the information provided on the lot grading plan.

The proposed parking for the top of the dwelling.s foundation walls shall be shown at the corners of the foundation.

Building parkings must show the relationship of the proposed building to the grades as specified on the subdivision.s approved lot grading plan. Any deviation to these grades must be identified. The proposed parking for the foundation walls shall be shown at the end of each side of the building. The attached sheets illustrate the above requirements.

A typical scaffold-frame shoring is schematically shown in Fig. 1. As stated previously, if a scaffold-frame shoring fails, it basically fails due to instability (buckling) problem as shown in Fig. 2. The proposed monitoring method is planned and designed to prevent the buckling failure. It is recommended that two key parameters, the axial forces and the lateral displacements (d shown in Fig. 2), be monitored in the field. Strain gauges are recommended for measuring the axial forces and linear variable differential transformers (LVDTs) for measuring the lateral displacements. The strain gauges and LVDTs should be installed at all the critical locations, where the larger axial forces and lateral displacements are likely to occur. The critical locations for monitoring the axial forces and lateral displacements, the allowable axial forces and the allowable lateral displacements are suggested on the basis of detailed analysis and laboratory experiments.

Fig. 1. A typical scaffold-frame shoring system.



Fig. 2. Buckling failure of scaffolds.

Accidents occur mostly during concrete placement. These accidents occur not only due to the concrete weight but also to non-uniform placement of concrete, or settlement of the scaffold foundation. In the case of failure caused by non-uniform concrete placement, because the local overload and buckling factors exist, the suggested monitoring method is still applicable. The suggested monitoring method is not suitable for the failure caused by foundation settlement.

Monitoring axial forces

Allowable axial forces

The allowable axial forces are suggested on the basis of the buckling loads of the scaffolds. According to the test results from Ref. [12], the buckling loads are

(1)

(2)

K=0.8+(N-1)×0.2,

where Pcr is the critical axial load for a scaffold at N story high, E is Young's modulus, I is the moment inertia of one pipe of a scaffold, L is one-story height of a scaffold, and N is number of stories.

The allowable axial forces on the scaffolds are suggested as

(3)

Pall=fc×Pcr

in which Pall is the allowable axial loads for a scaffold, and fc is the resistance reduction factor suggested to be 0.75 (referring to Fig. 11 by tests).

2.1.2. Way to install equipment for monitoring axial forces

It is recommended that four strain gauges be attached to the monitored vertical pipes of scaffolds as shown in Fig. 3 to measure the axial ...