Chapter 16, Problem 16.1CTP

BuyFind*arrow_forward*

9th Edition

Braja M. Das + 1 other

ISBN: 9781305970939

Textbook Problem

The following table shows the boring log at a site where a multi-story shopping center would be constructed. Soil classification and the standard penetration number, *N*_{60}, are provided in the boring log. All columns of the building are supported by square footings which must be placed at a depth of 1.5 m. Additionally, the settlement (elastic) of each footing must be restricted to 20 mm. Since the column loads at different location can vary, a design chart is helpful for quick estimation of footing size required to support a given load.

**a.**Prepare a chart by plotting the variation of maximum allowable column loads with footing sizes,*B*= 1 m, 1.5 m, 2 m, and 3 m. Use a factor of safety of 3.**b.**If the gross column load from the structure is 250 kN, how would you use this chart to select a footing size?**c.**What would be the design footing size for the column in Part (b) if you use Terzaghi’s bearing capacity equation? For the well graded sand, assume that*ϕ′*= 33°. Use*F*= 3._{s}**d.**Compare and discuss the differences in footing sizes obtained in Parts b and c.

(a)

To determine

Plot the variation of maximum allowable column loads with size of footings to prepare a chart.

Explanation

Given information:

The location of depth of footing

The given size of the footing *B* is 1 m, 1.5 m, 2 m, and 3 m.

The settlement of each footing

The given factor of safety

Calculation:

**For B value is 1 m:**

Determine the depth factor using the relation.

Substitute 1.5 m for *B*.

The

The field standard penetration number

Determine the depth of foundation for the field standard penetration number gets averaged.

Substitute 1.5 m for *B*.

Determine the averaged

Here,

Substitute 12 for

Determine the net allowable bearing capacity of the soil

Substitute 10 for

Determine the maximum allowable column load

Substitute *B*, and 3 for

**For B value is 1.5 m:**

Determine the depth factor using the relation.

Substitute 1.5 m for *B*.

The field standard penetration number

Determine the depth of foundation for the field standard penetration number gets averaged.

Substitute 1.5 m for *B*.

Determine the averaged

Here,

Substitute 7 for

Determine the net allowable bearing capacity of the soil

Substitute 8 for

Determine the maximum allowable column load

Substitute *B*, and 3 for

**For B value is 2 m:**

Determine the depth factor using the relation.

(b)

To determine

Find the footing size for the given gross column load of 250 kN.

(c)

To determine

Find the design column load for the footing size of 2.25 m using the Terzaghi’s bearing capacity equation.

(d)

To determine

Compare and discuss the differences in footing sizes obtained in parts (b) and (c).

Engineering Fundamentals: An Introduction to Engineering (MindTap Course List)

Fundamentals of Geotechnical Engineering (MindTap Course List)

Database Systems: Design, Implementation, & Management

Principles of Information Systems (MindTap Course List)

Mechanics of Materials (MindTap Course List)

Principles of Information Security (MindTap Course List)

Database Systems: Design, Implementation, & Management

Fundamentals of Information Systems

Precision Machining Technology (MindTap Course List)

Cornerstones of Financial Accounting

Automotive Technology: A Systems Approach (MindTap Course List)

Fundamentals of Information Systems

Solid Waste Engineering

International Edition---engineering Mechanics: Statics, 4th Edition

Fundamentals of Chemical Engineering Thermodynamics (MindTap Course List)

Management Of Information Security

EBK ELECTRICAL WIRING RESIDENTIAL

Electric Motor Control

Systems Analysis and Design (Shelly Cashman Series) (MindTap Course List)

Steel Design (Activate Learning with these NEW titles from Engineering!)

Automotive Technology

Structural Analysis

Welding: Principles and Applications (MindTap Course List)

Enhanced Discovering Computers 2017 (Shelly Cashman Series) (MindTap Course List)

Network+ Guide to Networks (MindTap Course List)