Calculation of Earthwork Wichita

Because the densities of Earthwork Wichita materials will change during excavation, handling, and placement, calculations related to earthwork—excavation, fill, riprap, etc.—differ from quantity estimates for other materials (e.g., concrete and steel). Regardless of the method used to compute the quantities, the following changes in volumes should be accounted for in earthwork calculations:

Materials excavated from natural sources (bank-run or pit-run materials) will increase in volume in the haul trucks and/or in the stockpiles. This increase in volume is known as swell. Materials that are compacted by mechanical equipment will decrease in volume when compared with loose stockpiles and sometimes when compared with bank-run materials. This decrease in volume is known as shrink. Another problem unique to earthwork relates to how it is paid for during construction. When aggregates filter materials, or riprap is paid for by weight, conversion factors must be used to convert the in-place quantities into weights.

Regardless of how these materials are paid, either the engineer or contractor needs to use conversion factors for the following reasons: When materials are paid for by weight, the engineer needs to convert in-place volumes to weights. Because these materials are purchased and hauled based on weight, the contractor does not need the conversion process. The contractor prefers this method. When materials are paid for by in-place volume, the engineer does not need to use the conversion factors; that responsibility is shifted to the contractor. Not only does the contractor have to convert the materials from weights to volumes, he or she also must estimate the effects of swelling and shrinking during borrowing, stockpiling, and compaction and losses during the handling process. The engineer prefers this method.

Swell factors and shrink factors can be used to account for changes in densities of excavated and compacted Earthwork Wichita. Civil and mining engineers have used these factors for more than 100 years. By virtue of the different natural methods of formation, deposition, and soil com­position, bank-run soil materials are highly variable. The percent swell and percent shrink shown in the table are dependent on the bank-run conditions and represent only the average conditions. Loosened conditions are also highly variable, depending on a number of factors, such as method of excavation, moisture condition of the soil, and cohesion char­acteristics.

The percent swell and percent compact in the table, which are depen­dent on the loosened conditions, represent only the average conditions. Compacted density is also highly variable, depending on a number of factors, such as the loose-lift thickness, size and type of the compaction equipment, and in-place moisture content. The percent shrink and percent compact shown in the table arc dependent on the compacted density and represent only the average conditions.

The Author is a professional writer, presently writing for http://www.excavationcontractorswichita.com

Sponsor Ads

• Ad Space Available - Rent it Now!

Report this Page

Created on Dec 31st 1969 18:00. Viewed 0 times.

Share on APSense

Comments