GEOL 1 CHAPTER 8

• London Bridge so well known through illustrations in history books appears to have been completed in the early part of 13th century
• London Bridge was made for wise men to go over and fools to go under
• Act of Parliament in 1756 ordered that all the buildings on the bridge to be removed and the two central arches rebuilt into the arch
• The careful consideration of foundation materials is as challenging as the determinate mathematical calculations relating to the arrangement of steel, reinforced concrete or timber to be used for the superstructure The Importance of Bridge Foundations
• The first considerations in bridge location are generally those of convenience and economy Special Preliminary Work
• Riverbeds contain many types of deposits including boulders, extensive boulder can be easily mistaken as solid rock
• Engineers decided upon a program of borings and soil testing to enable them to: 1. To determine the nature of the subsurface materials 2. To ascertain the most desirable location for the center line of the bridge 3. To determine the best location for individual piers 4. To select a logical basis for the design of the piers
• DESIGN OF BRIDGE PIERS Four types of bridge-pier loading -Vertical loads -Inclined loads -Inclined tensions -Horizontal thrust
• Two unusual features that may require reductions of the calculated net load: -allowance for the natural material excavated and for the displacement by the pier -the reduction for skin friction on the sides of the pier
• Geologic information can be applied to predict settlement of loaded piers: -Displacement by scour -Lateral displacement due to lack of restraint - Consolidation of the underlying material -Failure of an underlying stratum
• North Main Pier is founded in Basalt Basalt- a hard, dense, dark volcanic rock South Main Pier is founded on Sandstone Sandstone- a sedimentary rock formed by consolidation and compaction of sand
• INSPECTION AND MAINTENANCE: All civil engineering structures require a regular and thorough inspection
• Lethbridge Viaduct - An outstanding example of benefit work, commonly known as the High Level Bridge
• Rhaetian Railway - has the largest networks of all the private railways in Switzerland
• Grouting has become one of the most widely used specialty techniques in the practice of Civil engineering
• Grout involves the injection of semi viscous or slurried material into earth material, under pressure and through specially drilled holes
• TOOLS ASSOCIATED WITH APPLYING AND REMOVAL OF GROUT: -Grout Saw or Grout Scraper — a manual tool for removal of old and discolored grout. The blade is usually composed of tungsten carbide. -Grout float — A trowel-like tool for smoothing the surface of a grout line, typically made of rubber or soft plastic. -Grout sealer — a water-based sealant applied over dried grout that resists water, oil and acid-based contaminants.
• ASCE- also known as American Society of Civil Engineers and Architects -It was founded in New York City on November 5, 1852 -ASCE was the first national engineering society created in the United States