Wind loads

Fig. 1. Wind-load data for he at-strengthened and laminated 3.2-mm glass. Architect s specified probabiUty of breakage is 8/1000 laminates for a 1-min uniform wind-load duration. Four sides supported in weathertight rabbet. Curves for different glaring areas A, 0.93 m (10 ft ) B, 1.39 m (15 ft ) C, 1.86...

This Cg can then be used in the original filU-scale spherical storage tank to calculate its wind load (eq. 35) ... 

Wind Load Design Criteria Wind load criteria for design of structure, buildings, towers, etc, and their parts shall conform with the requirements of the... 

BS Code of Practice CPS. 1972. Chapter V Loading, part 2 Wind loads. British Standards Institution, London. 

The derrick or mast must also be designed to withstand wind loads. Wind loads are imposed by the wind acting on the outer and inner surfaces of the open structure. When designing for wind loads, the designer must consider that the drill pipe or other tubulars may be out of the hole and stacked in the structure. This means that there will be loads imposed on the structure by the pipe weight (i.e., setback load) in addition to the additional loads imposed by the wind. The horizontal forces due to wind are counteracted by the lattice structure that is firmly secured to the structure s foundation. Additional support to the structure can be accomplished by the guy lines attached to the structure and to a dead man anchor some distance away from it. The dead man anchor is buried in the ground to firmly support the tension loads in the guy line. The guy lines are pretensioned when attached to the dead man anchor. 

Mast setup distance The distance from the centerline of the well to a designated point on the mast structure defined by a manufacturer to assist in the setup of the rig. Maximum rated static hook load The sum of the weight applied at the hook and the traveling equipment for the designated location of the dead line anchor and the specified number of drilling lines without any pipe setback, sucker rod, or wind loadings. 

API Standard 4A (superseded by Standard 4F) provides rating of derrick capacities in terms of maximum safe load. This is simply the load capacity of a single leg multiplied by four. It does not account for pipe setback, wind loads, the number of lines between the crown block and the traveling block, the location of the dead line, or vibratory and impact loads. Thus, it is recommended that the maximum safe static load of derricks designed under Standard 4A exceed the derrick load as follows ... 

Under the rigging conditions given on the nameplate, and in the absence of setback or wind loads, the static hook load under which failure may occur in masts conforming to this specification can be given as only approximately twice the maximum rated static hook load capacity. 

Each structure shall be rated for the following applicable loading conditions. The structures shall be designed to meet or exceed these conditions in accordance with the applicable specifications set forth herein. The following ratings do not include any allowance for impact. Acceleration, impact, setback, and wind loads will reduce the rated static hook load capacity. 

Hook load, wind load, vessel motions, and pipe setback in combination with each other for the following ... 

Operating loads (no wind loads) composed of the following loads in combination ... 

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