1. WELCOME

2. COMPOSITE NOISE BARRIERS IN
DEVELOPMENT OF STEEL
COMPOSITE NOISE BARRIERS IN
HIGHWAYS
PRESENTED BY :
FEBIN T S
S7 MECHANICAL
ROLL NO : 4430

3. INTRODUCTION
Development of steel composite noise barrier due to the growing consciousness of noise pollution.
To reduce noise level by 5 to 25 dB from 70 to 90dB on busy roads and highways.
Appropriate design, acoustic performance and cost of prototype.

4. MECHANISM OF NOISE PROPOGATION
Noise propagates through either solid, liquid or gas.
Presence of barrier reflects, diffracts and transmits sound energy without following a direct path.
Sharp or multiple edges of a barrier diffract or split sound waves and reduce intensity.

5. SOUND TRANSMISSION LOSS OF VARIOUS MATERIALS
Thickness
(mm)
Surface Density (kg/m2)
Transmission
Loss (dB)
Concrete
100
244 40
Brick
150
288
Steel
1.27
9.8 25
Aluminium
1.59
4.4 23
Wood 18 21
Plywood
16.1

6. WORKING OF NOISE BARRIER

7. SCHEMATIC DIAGRAM OF ABSORPTIVE PANEL
GLASS FIBER MAT WRAPPED IN NYLON
COLD FORMED GALVANISED SHEET
SLOTTED GALVANISED
SHEET
TRAPEZOIDAL RIBS
ON BACK PLATE
SCHEMATIC DIAGRAM OF ABSORPTIVE PANEL
BACK

8. PROTOTYPE BARRIER

9. ACOUSTIC MATERIALS
Absorbing materials (porous): glass wool, open cell polyurethane foam.
Barrier materials (heavy): metal, stone, glass etc. A higher mass of which leads to higher transmission loss of noise.
Damping materials: felt and thermocol dampen structural vibration to prevent resonance.

10. DESIGN CONSIDERATIONS
Acoustic considerations based on existing and desired noise levels in the protected area.
Height depends on desired shadow zone.
The bottom portion (around 1.8m above ground) is made of absorptive panels.
Wind load and structural rigidity.

11. DESIGN CONSIDERATIONS
Transparent panels are used to permit ingress of light. Reflective panels at higher elevations.
To maximize performance to cost ratio total height of barrier varies between 2.8 to3.2m.
Parallel reflective barriers width to height ratio of roadway to barriers should be at least 10:1,to avoid reduction in performance due to multiple reflections.

12. MATERIAL FOR NOISE BARRIER
Reinforcement – glass fiber which are silica based and contains oxides of Ca, B, Na, Al, Fe etc.
Reinforcement can be in the form of particles, whiskers, continuous fibers or sheets.
Composite materials have fibrous reinforcement as its more stronger and stiffer than any other form

13. COMPOSITION OF PANEL Continuous glass fiber is used as reinforcement.
Core of panels is filled with glass fiber, wrapped in nylon net which provides excellent sound absorbing capacity.
Cold formed galvanized sheets have been used to provide structural rigidity and to possess better transmission loss.

14. NOISE BARRIERS USED ABROAD

15. APPLICATIONS Railway tracks in metro cities.
Railway switchyards, bridges and tunnels.
Airport terminals and boundaries.
Enclosures for noisy equipments.

16. THANK YOU