What is a concrete approach slab?
Approach Slab. APPROACH SLABS. The approach slab provides a transition between roadway pavement and the bridge. The approach slab acts as an intermediate bridge to span the portion of embankment directly behind the abutment/backwall which was excavated to construct the abutment/backwall.
What are approach slabs?
Approach slab (relieving slab, run-on slab or transition slab) describes the reinforced concrete slab which supports the road-surface at the transition from an approach embankment to a bridge abutment or culvert or adjacent to a retaining wall.
What is the purpose of approach slab?
The purpose of the bridge approach slab is to significantly reduce local settlement and to accommodate global settlement by providing a gradual transition between the roadway and the bridge deck.
How long are approach slabs?
VDOT approach slabs are typically 6.1 m (20 ft) long and of pavement width unless the shoulder has a full-depth pavement, in which case the slab width is extended across the shoulder.
What is transition slab?
For longer bridges, a transition slab is used to accommodate the larger movements occurring at the bridge ends, avoiding the formation of transverse bumps and dips as well as cracking of the pavement.
What is friction slab?
Friction slab shuttering is used along the sides of bridges. These shuttering consists of slab of the bridge along with crash barrier shuttering. Making it a one full assembly. These are provided with pockets to let pass the drainage pipes etc. as required per design.
How do slab bridges work?
Slab bridges are monolithic, flat concrete beams (slabs) with twisted or roughened reinforcing steel rods concentrated in the lower portion and at either end of the slab, where tensile forces and sheer are the greatest. The amount of steel and depth of the slab are based on its length and live-load capacity.
What is a sleeper slab?
A SLEEPER SLAB is a reinforced concrete block supporting the end of the concrete approach slab at the approach roadway end. It is typically used when preformed elastomeric compression joint seals are not used between the concrete pavement sections.
What is crash barrier in bridge?
Median Barriers– These are used to put a stop to vehicles from crossing over a median and striking an oncoming vehicle in a head-on crash. Bridge Barrier – This is planned to hold down vehicles from crashing off the side of a bridge and falling onto the roadway, river or railroad below.
Can water reduce friction?
Water usually reduces friction between two surfaces. Whether water acts as a lubricant or not depends on the nature of the two surfaces. For water to reduce friction, it must reduce the contact area between two surfaces by separating them and acting as a barrier.
How thick does concrete need to be for a bridge?
For the bridges tested, spans ranged from 8 ft to 20 ft, widths ranged from 26 to 47 ft, aspect ratios from 0.17 to 0.68 and slab thickness from 10 to 18 inches.
What to do with a concrete slab?
Concrete slabs are essential to the structural stability and design of modern buildings. A single, thick concrete slab is often used as the foundation for large buildings – called “Slab-on-Grade Foundation” – resting on compacted subsoil and ensuring the building stays level.
What is an approach slab?
approach slabs. The approach slab provides a transition between roadway pavement and the bridge. The approach slab acts as an intermediate bridge to span the portion of embankment directly behind the abutment/backwall which was excavated to construct the abutment/backwall.
What goes into a concrete slab?
– Sweep away any dirt and debris from the area. – Dig out and remove all the old material that’s in the joints with a putty knife. – With a wet-dry vacuum, clean out the joints between the slabs very well. – Apply a bonding adhesive, usually epoxy, into the joints with a brush. – Insert foam backer rod. – Cover and seal the joint.
What is concrete approach?
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