Chapter 4-5 Discussion

 

Sumerian classroom, 2000 BC  source

Modern classroom, 2010 AD  source

 

. B6 - create - Design a truss that would cost half as much but last twice as long.
B5 - optimize - Minimize the truss' weight, cost, etc.
60% - B4 - compare - Which truss is the safest for the given loads?
70% - B3 - calculate - Calculate the force in each truss member.
80% - B2 - understand - Identify all of the special joints.
90% - B1 - read - Label the following trusses.

 

 

 

 

Chapter 4 - design concepts

 

At least 19 dead in Tanzania building collapse - March 31

police detained three engineers for questioning

Death toll rises to 72 in India building collapse - April 6

Bangladesh building collapse kills more than 70 - April 24

supervisors had ordered them to attend work on Wednesday, even though cracks were discovered in the building on Tuesday

Hospital roof collapses in India, injuring 8 - April 26

 

 

1164 lb @ 3.7"

FS = 5.06		 d = NL/EA

2903 lb @ 1.5"

FS = 6.45

D = 0.375", n = 16

33 or 55 ksi proof strength

thread area = 0.7854 (D-0.9743/n)2 = 0.07749 in.2

6700 lb = 86,500 psi

FS = 1.57 or 2.62

 

 

 

 

Ozark Machinery Company
West Plains, Missouri
Serco 8000 Log and Pulp Loaders
pin 1

bridge pins

1, 2, 3
pin 2
pin 3
u-joint
pin 4

 

 

 

Three Chinese Engineers Arrested Over India Chimney Collapse
BBC News (1/13/2010)

"Three Chinese engineers have been arrested in connection" with a chimney collapse last year in India. "A chimney caved in on workers during construction at a thermal power plant in Korba district, killing 41 people last September" in the state of Chhattisgarh. "It is not yet clear what caused the accident, but officials from all companies involved have been detained. Police have already arrested four officials from two Indian firms in connection with the incident."

Negligence factor in Russian power plant accident

Russia's top industrial safety oversight official said Saturday that negligence was a major factor in a devastating accident at the country's biggest hydroelectric power plant, and hinted that high-level officials could face trial over the disaster that killed 75 workers. ... Part of an overstrained turbine unit weighing 1,500 tons snapped off its restraining bolts and sailed into the air, he said, unleashing flooding, short circuits and wreckage that crippled the plant and doomed dozens of workers in seconds. ... After it came apart, the ruined unit acted as a powerful pump, swiftly flooding the area with water, and two other units continued to operate under water for more than minute, causing "massive short circuits," he said. The plant was soon without power, crippling safety systems. ... The bolts that failed to hold the turbine-generator unit in place were badly worn before the accident, and it had been vibrating more than it should have been weeks earlier — and then even more dangerously in the hours before the accident, Kutin said. ...

 

 

source source
Faulty Design Led to Minnesota Bridge Collapse, Inquiry Finds

Investigators said Monday that the Interstate 35W bridge in Minneapolis, which collapsed into the Mississippi River on Aug. 1, killing 13, came down because of a flaw in its design.  The designers had specified a metal plate that was too thin to serve as a junction of several girders, investigators say.  ...  The I-35W bridge was of a type called “fracture critical,” meaning that the failure of any major member would cause a collapse, because it had no redundancy. The design is lighter and less expensive to build, but has gradually fallen out of favor with highway departments.

Controversy Dogs Inquiry on Bridge Collapse

The design of the bridge that failed was no good from the day the span opened, the board said: an engineer in the mid-1960s had specified gusset plates, the big sheets of steel that tie girders together, of half-inch thickness when they should have been an inch thick.
 
source

 

 

In-Flight Separation of Vertical Stabilizer American Airlines Flight 587

All 260 people aboard the airplane and 5 people on the ground were killed...  The National Transportation Safety Board determines that the probable cause of this accident was the in-flight separation of the vertical stabilizer as a result of the loads beyond ultimate design that were created by the first officer’s unnecessary and excessive rudder pedal inputs. Contributing to these rudder pedal inputs were characteristics of the Airbus A300-600 rudder system design and elements of the American Airlines Advanced Aircraft Maneuvering Program.

source

 

hook failure

chain/hook failure

Engineer in Building Collapse Gives Up His Florida License

Panel Revokes Licenses Of Two Hyatt Engineers, Engineers Charged with Negligence in Kansas City Hotel Disaster

 

 

 

 

 

 

 

 

props: aluminum welding rods, spring, toddler chair