Pile Load & Test Data

Costs of land, labor and materials continue to escalate. Thus the need for piles that consistently deliver higher design load capacities have become increasingly economically critical to the deep foundation aspects of any heavy construction project.

To verify the feasibility of higher design loads, a pre-design comparative test pile program is being conducted more frequently. Here, the performance and compatibility of soil, hammer and pile types can be established prior to bidding, eliminating many unknown factors, in turn minimizing foundation costs.

The interaction between pile profile and soil-bearing strata are of prime importance. Utilizing the most effective pile shape can result in substantial pile length savings. Soil set-up can aid in shorter pile lengths and lower pile hammer blow count requirements, all of which contribute to a lower installed pile cost-per-ton-supported.

Spanning over eight decades of successful installations, a wealth of design, test and installation data has been accumulated. This data not only proves the benefits of Monotube foundation piles, but also provides supporting documentation to help users successfully design and specify the use of Monotube piles in their own projects. We urge you to contact us for this free, informative reference resource book.

Allowable Pile Loads

as determined by Engineering News Formula

Graph for Light Piles (
Wp/Wh
assumed equal to one)
Allowable Pile Loads chart

Engineering News Formula

engineering news formula

P = Allowable pile loads in pounds

Wp = Weight driven in pounds

Wh = Weight of striking part of hammer in pounds

H = Actual height of fall of striking hammer in feet

E = Actual energy delivered by the hammer blow in foot-pounds

S = Penetration of pile per blow, in inches, after the pile has been driven to a depth where succesive blows produce approximately equal net penetration

The value
Wp/Wh
shall never be taken as less than one.

Although Monotube Pile does not endorse the use of any formula, many dynamic pile driving formulas have been developed as an aid in determining pile capacity. Such formulas serve a useful purpose particularly on small projects, or where previous experience and static testing in a given area have confirmed their reliability.

The modified Engineering News Formula, which takes into account the relationship between the relative weights of the pile and hammer, is commonly used.

This formula has proven to be most reliable when uniformly tapered piles are embedded in a cohesionless bearing stratum.

Foundation engineers recognize the varying results with any formula, or static analysis approach, in the determination of pile capacity and/or length. The reliability of soil information, its variability within the site, the selection of appropriate soil values, pile shape, hammer efficiency, and the effect of pile driving forces on in-situ soil conditions are among the variables which influence pile performance and require sound engineering judgement.

On large projects involving high capacity piles, predesign or prebid programs incorporating static load tests, or dynamic methods coordinated with static tests can provide rational driving criteria resulting in substantial cost savings.