The Civil Engineer

Structural Engineering Marvels : Rolling Bridge

Building big isn't the only way for engineers to make an impression. The Rolling Bridge, which allows pedestrians to walk over the Grand Union Canal in London, spans just 39 feet (11.8 meters). But its innovative design more than makes up for its diminutive stature. The bridge consists of eight timber-and-steel sections hinged together so that, fully extended, it lies flat. Then, under action of hydraulic pistons, the sections can lift and pivot to allow the entire structure to curl upon itself, much like a pill bug rolling into a ball. While boats pass through the unobstructed canal, the bridge sits on the bank like a piece of sculpture.

The Rolling Bridge is the brainchild of Thomas Heatherwick, who has designed other architectural oddities, such as the giant cauldron that burned during the opening ceremony of the 2012 Olympic Games in London and the B of the Bang starburst sculpture. In 2008, the city of Manchester asked Heatherwick to take down B of the Bang because it kept shedding spikes. So far, the Rolling Bridge has presented no such dangers. In fact, in 2005, it received a Structural Steel Design Award, with the judges noting that the bridge was a "joyful addition to the [Paddington Basin] development area that has all the appearance of a Leonardo sketch when in the 'rolled' position."

Structural Engineering Marvels : Laerdal Tunnel

To connect the Norwegian cities of Laerdal and Aurland highway engineers were forced to solve a small problem: the Hornsnipa and Jeronnosi mountains. Instead of going around the obstacles, they decided to go through them. The result was the Laerdal Tunnel, which runs through solid gneiss rock for 15 miles (24 kilometers), earning it the title of the world's longest completed road tunnel.

Excavating such a structure is only one of the challenges. Designers also have to ensure that motorists can make the long, underground trek without succumbing to "highway hypnosis." To address this problem, the Norwegian Public Roads Administration called in a team of psychologists to make sure the finished roadway was as stimulating as possible. The agency recommended including blue lights and gentle curves to keep drivers engaged. They also suggested that the final tunnel be divided into four sections to help reduce monotony.

Motorists entering the Laerdal Tunnel today might not notice these design enhancements, but they'll certainly appreciate them when they emerge safely into daylight after the 20-minute journey through the middle of a mountain.

Live loads are different for different buildings and structures. It keeps changing from time to time even on same structure. Examples for live loads are weight of persons, movable partitions, dust loads, weight of furniture etc. These loads should be suitable assumed by the designed. It is one of the major loads in structural design. The minimum live loads per square meter area for different types of structures are given in IS 875 (Part-2)-1987.

http://thestructuralengineer.blogspot.in/2015/06/live-loads-for-different-building-floors.html

Live loads for different building floors | Structural Engineering Knowledge Sharing

De-shuttering period

CiViL Engineering