Heavy Equipment Icons


What are some iconic types of Heavy Equipment in the industry?


D10 Dozer – Operating Weight: 154,700 lbs (Caterpillar)

772 Off Highway Truck (Caterpillar)

Gross Operating Weight: 181,000 lbs, Payload: 50 tons, Heaped: 41 cu. yd.


992 Wheel Loader – Bucket Capacity: 14 to 16 cu. yd. (Caterpillar)

Construction Equipment | Construction Industry Product Information

Design Earthquakes – Definitions

For Concrete Structures: OBE (operational basis earthquake) = 144-yr Return Period (50 percent chance of being exceeded in 100 years).

Max. Design EQ: for Structures Defined As Critical use MCE, In general for other structures, MDE = 950-yr return period (10 percent chance of being exceeded in 100 years).

MCE is defined as the greatest earthquake that can reasonable be expected to be generated by a specific source (which comes from a deterministic site hazard analysis).

USACE references: Stability Analysis of Concrete StructuresEarthquake Design and Evaluation of Concrete Hydraulic StructuresEarthquake Design and Evaluation for CW ProjectsSafety of Dams – Policies and Procedures.

Dam Failures in March – St. Francis Dam Disaster


St Francis Dam Failure, 12 March 1928.  Failed catastrophically upon its first full filling, near midnight, killing at least 450 people.  Seepage (dirty water)  was observed the day of the failure. A massive landslide occurred in the dams left abutment, comprised of schist.

“Greatest American civil engineering failure in the 20th century.”

Remaining Portions of Dam After Failure.

Historical Society of Southern California:  St. Francis Dam Disaster.

Excellent Photo Display at:  St. Francis Dam collapse – Framework – Photos and Video – Visual Storytelling from the Los Angeles Times.

Type: Concrete Gravity Thick Arch Dam, Maximum Height = 195 feet, Storage (at time of failure) = 38,000 acre-feet