FRAMING SEMINARS 2012PRESENTED BY

KW ENGINEERING

1

The Instructor – Who am I Ken Watters II, P.E. 42 years old Penn State

Graduate. Currently registered structural engineer in 8 states. I have appeared as an expert witness in both truss

and code related court cases. 25+ years of experience in construction. Much of my experience has come hands on in the

field. I am a practicing engineer with my own small firm. Offices in PA and CO. Love the mountains and the outdoors. Avid Downhill and Backcountry Skier.

2

3

Engineering design from Mountain Top to Coast.

East Coast2053 West Woodbine Rd.

Airville, PA 17302

Rocky MountainsP.O. Box 1792

637 Platte River Dr.Fairplay, CO 80440

4

IRC International Residential Code

5

Outline Prescriptive Foundation Design Per

IRC 2009

Existing and new practices that are outside the scope of the IRC are permitted as an engineered design.

6

Today’s Homes & IRC Scope

Wood Framed Buildings ≤ 36 ft. in width ≤ 60 ft. in length ≤ 3 stories above grade in height 3:12 ≤ roof slopes ≤ 12:12

Portions of structures outside these geometry limitations are outside the scope of the IRC Expected to be designed by an architect

or engineer

7

Today’s Homes & IRC Scope Restricted to buildings within stated

regions: Basic wind speeds less than 100 mph in

hurricane-prone regions, or less than 110 mph elsewhere

Ground snow load is 70 psf or less Special requirements are included for regions

having a seismic design category designation of C, D0, D1, or D2

Portions of structures outside these geometry limitations are outside the scope of the IRC Expected to be designed by an architect or

engineer IRC’s code provisions may be inadequate,

misunderstood or misapplied.

Common issues outside the scope of

the IRC

8

Buildings with Steel Beams Foundation walls laterally unsupported at

the top (>4’ tall) Tall walls over 12’ Discontinuous wall foundations Floor systems deeper than 16”

9

Overview of Issues

A little of what not to do!Courtesy Aries Engineering

Continuous Foundations

Can a wall footer that requires a step due to grade conditions be discontinuous?

10

Inside of crawl space

11

Close-up

12

Top of higher footer

Top of lower footer

2x Wood “Bridge”

R403.1 General. All exterior walls shall be supported on continuoussolid or fully grouted masonry or concrete footings,crushed stone footings, wood foundations, or other approvedstructural systems which shall be of sufficient design to

accommodateall loads according to Section R301 and to transmit theresulting loads to the soil within the limitations as determinedfrom the character of the soil. Footings shall be supported onundisturbed natural soils or engineered fill. Concrete footingshall be designed and constructed in accordance with the

provisionsof Section R403 or in accordance with ACI 332.

13

R403.1.5 Slope. The top surface of footings shall be level.The bottom surface of footings shall not have a slopeexceeding one unit vertical in 10 units horizontal (10-percentslope). Footings shall be stepped where it is necessaryto change the elevation of the top surface of the footings orwhere the slope of the bottom surface of the footings willexceed one unit vertical in ten units horizontal (10-percentslope).

14

Figure R403.1.5

15

Foundation depthR403.1.4 Minimum depth. All exterior footings shall

beplaced at least 12 inches (305 mm) below the

undisturbedground surface. Where applicable, the depth of

footings shallalso conform to Sections R403.1.4.1 through

R403.1.4.2.

16

Inside and Outside of the building for Exterior Footings?

What is the definition of Undisturbed Ground Surface? Is this the height or grade of the ground before excavation or after

construction and backfilling are complete?

Exposed Crawl Space Footing

17

Bottom of footing

Lateral Wall Support

18

R404.1.3 Design required. Concrete or masonry foundation

walls shall be designed in accordance with accepted

engineering practice when either of the following conditions

exists:

1. Walls are subject to hydrostatic pressure from

groundwater.

2. Walls supporting more than 48 inches (1219 mm)

of unbalanced backfill that do not have permanent

lateral support at the top or bottom.

Lateral Wall Support

What constitutes lateral support for the top and bottom of the wall

19

Lateral Wall Support

Bottom of wall

Slab most common How much Dirt or stone would you need?

Passive vs. Active pressures

20

Lateral Wall Support

Top of wall

Less force than the bottom Often wood sill plate supported by

floor joist and subfloor. Can an end joist by itself support

the top of a foundation wall?

21

Lateral Wall Support

22

23

PRESENTED BYKW Engineering

Web: kweng.net email: ken@kweng.net

KEN WATTERS II, P.E.717-862-3455