Table of Contents
- 1 What is prestressed box girder?
- 2 What is the purpose of a box girder?
- 3 How do you make a box girder?
- 4 How does a box beam work?
- 5 Which bridge carries the most types of transport?
- 6 Can a universal beam be used as a column?
- 7 What grade of concrete is used in prestressing technique?
- 8 What is the thickness of the bottom flange of box girder?
What is prestressed box girder?
A box girder bridge, or box section bridge, is a bridge in which the main beams comprise girders in the shape of a hollow box. The box girder normally comprises prestressed concrete, structural steel, or a composite of steel and reinforced concrete.
What is the purpose of a box girder?
Box girders are used for the construction of a cable-supported bridge, curved bridge, and footbridges. It is rarely used in buildings, but they may be used in special circumstances, such as when loads are carried eccentrically to the beam axis.
What is segmental box girder?
Segmental Box Girder Bridges Single or multiple cell box sections are generally used for the superstructure. The segments may either be cast-in-situ or precast/prefabricated. The post-tensioning system can be bonded, unbonded, or a combination of both.
How do you make a box girder?
One of the most commonly used forms of superstructure in concrete bridges is precast girders with cast-in-situ slab. This type of superstructure is generally used for spans between 20 to 40 m….Analysis and design of prestressed concrete box girder bridge.
| Eccentricity (mm) | Prestressing Force (kN) | The eccentricity which give minimum prestressing force (e) = 731mm |
|---|---|---|
| 731 | 16489.15 |
How does a box beam work?
Box beams are beams that are created using sections of lumber, along with plywood sheets. Metal versions are often made using lengths of forged metal along with some type of metal coating or sheeting for additional strength. Unlike a solid beam, a box beam is hollow on the inside.
Why a box girder bridge is made hollow?
use in bridge construction The hollow box gave the deck the extra stiffness of a truss, but it was easier to build and required less engineering precision—at the cost, however, of extra material.
Which bridge carries the most types of transport?
Girder bridge
| Two different girder bridges. The top is a plate girder bridge, while the bottom is a concrete girder bridge. | |
|---|---|
| Ancestor | Beam bridge |
| Carries | Pedestrians, automobiles, trucks, light rail, heavy rail |
| Span range | Short, Medium |
| Material | Iron, wood, concrete |
Can a universal beam be used as a column?
UC – universal column or UB – universal beam. Universal columns are the most often used sections for structural steel purposes. Universal columns are mainly used for columns, however, their small depth compared to universal beams make them ideal load bearing members when height is limited.
Is there a post-tensioned box girder design manual?
NCBC proudly sponsored a presentation by noted bridge engineer and author John Corven on FHWA’s Post-Tensioned Box Girder Design Manual. Mr. Corven spoke to a group of university professors at PCA’s annual Professors’ Workshop.
What grade of concrete is used in prestressing technique?
In reinforced concrete members, the prestress is commonly the steel reinforcement. The minimum grade of concrete in prestressing technique is M40 for pre tensioning and M35 for post tensioning. The tensile strength of concrete is only 8-14\% of its compressive strength of concrete. Fig1.1.
What is the thickness of the bottom flange of box girder?
The thickness of the bottom flange of box girder shall be not less than 1/20 th of the clear web spacing at the junction with bottom flange or 200 mm whichever is more. Thickness of Top Flange: