SPAN = 21m

WATER

LEVEL VARI-

ANCE

= 4m

ABUTMENT A:

4m X 4m X 2m

HIGH GABION

ROCK BASKET

HANDRAIL

TRUSSES: SIMPLY

SUPPORTED BE-

TWEEN ABUT-

HANDRAIL BRACING

AND FLOOR BEAMS

AT 3m cts

6m LONG ‘W-SHAPED’

TRUSS MODULES

SPLICED TOGETHER

ABUTMENT B:

GABION ROCK BASKET

CUT LIGHTLY INTO

ROCK

EXISTING BRIDGE

CAN BE USED DUR-

ING CONSTRUCTION

HANDRAIL BRACING AT

3m cts: SINGLE BAM-

BOO MEMBERS LASHED

TO HANDRAIL

NOTE: ALL BAMBOO

MEMBERS SOURCED

LOCALLY, TO BE 70-

100mm dia. X 15mm

THICK MOSO BAMBOO

BRIDGE WIDTH = 2m

DECK SURFACE:

HEAVY DUTY WIDE-

WEAVE BAMBOO

MAT

DECK JOISTS SIDE-BY-

SIDE BAMBOO POLES DECK BEAMS:

TRIPLED BAMBOO POLES PRO-

TRUDE LATERALLY, SUPPORTING

BRACING STRUTS

TRUSS CHORDS &

STRUTS: DOUBLE D

BAMBOO MEMBERS

TRUSS

HEIGHT =

1.5m

N.T.S. N.T.S.

N.T.S.

EXISTING

ROCKS

HIGH WATER LEVEL

HEIGHT OF

DECK ABOVE

HWL = 1m

MARINE-GRADE PLYWOOD GUSSET

PLATES (IMPORTED)

SIDE ELEVATION PLAN

TYPICAL SECTION ISOMETRIC

WZQ Bridge Design Competition 2010 · B AMB O O TR USS B R IDGE ·

LARGE STEEL CAGE ‘GABION BASKETS’ FILLED

WITH ASSORTED RIVER STONES CUT

INTO HILLSIDE.

ABUTMENT A TO BE CUT SUBSTANTIALLY

INTO EARTH TO PREVENT EROSION

FROM RIVER FLOW

ABUTMENT B NOTCHED INTO ROCK FOR

MECHANICAL ‘KEYING’ ON ABUTMENT

POSITION

WZQ Bridge Design Competition 2010 · B AMB O O TR USS B R IDGE ·

• HEAVY DUTY 5mm THICK WIDE-WEAVE

BAMBOO MAT OR EQUIVALENT, LOCALLY

AVAILABLE MATERIAL.

• IMPORTED IN 3m LONG PANELS (DOUBLED

OR TRIPLED IN THICKNESS IF NECESSARY.

• TIED AND/OR BOLTED THROUGH DECK

JOISTS DOWN TO DECK BEAMS FOR USE AS

OVERALL LATERAL BRACING

ABUTMENTS

HANDRAIL TRUSSES

HANDRAIL BRACING

DECK BEAMS

DECK JOISTS

STRUCTURAL ANALYSIS

• ASSUMED LIVE LOAD = 4kPa (PEOPLE & LIVESTOCK)

• GSA MODEL ANALYSED (SHOWN BELOW) : LL DEFLECTION = 200mm

DESIGN FEATURES

• LOCALLY-SOURCED, DURABLE MATERIALS WITH LOW EMBODIED CARBON: BAMBOO,

PLYWOOD, LOCAL RIVER STONES

• SIMPLE, MODULAR, CAN BE LIFTED MANUALLY IN PLACE AND MAINTAINED BY UN-

SKILLED WORKERS WITH MINIMAL DIRECTION

• TRUSS IS EFFICIENT, HAS A HIGH STRENGTH/WEIGHT RATIO & IS SAFE FOR USERS

• LOW COST PER METRE LENGTH, WITH FAST CONSTRUCTION TIME

• ENTIRE STRUCTURE CLEAR OF WATER FLOW

• REDUNDANCY IN DESIGN: TRUSS MEMBERS DOUBLED OR TRIPLED IN CASE OF FAILURE

OF SINGLE POLE

DECK SURFACE

• ROWS OF BAMBOO POLES LASHED TO-

GETHER USING BAMBOO LASHING OR ROPE.

• SPANNING 3m (LONGITUDINALLY) BETWEEN

DECK BEAMS

• 3-6m LONG PANELS SPLICED TOGETHER

USING BAMBOO OR ROPE LASHING

• 3NO. BAMBOO POLES LASHED & WEAVED

TOGETHER SPANNING 2m BETWEEN HAND-

RAIL TRUSSES BOTTOM CHORDS, EXTENDING

OUTWARDS TO SUPPORT BASE OF HANDRAIL

BRACING.

• CONNECTIONS LASHED WITH MULTIPLE BAM-

BOO STRANDS

• NOT CONNECTED AT NODES FOR EASE OF

CONSTRUCTION.

• BRACES HANDRAIL AGAINST COMPRES-

SION BUCKLING AND TRANSFERS LATERAL

HANDRAIL LOAD TO DECK BEAMS

• SINGLE BAMBOO POLE TIED & THROUGH-

BOLTED TO HANDRAIL AND DECK BEAMS.

BAMBOO LOCALLY-REINFORCED AT CON-

NECTIONS WITH GROUT

• MIDDLE POLE STOPPED SHORT TO ALLOW

‘SANDWICHING’ OF BRACING MEMBER.

• TRUSSES FABRICATED EITHER ON OR OFF

SITE IN ‘W-SHAPED’ MODULES

• POLES ARE BOLTED THOUGH GUSSET

PLATES, LASHED AND INTERNALLY REIN-

FORCED AROUND BOLTS TO PREVENT

SPLITTING.

• ALL MEMBERS DOUBLED UP (SIDE-BY-

SIDE) TO ‘SANDWICH’ IMPORTED PLY-

WOOD GUSSET PLATES

• SIMPLY-SUPPORTED BETWEEN ABUTMENT

BASKETS. , ALLOWING WETTING/DRYING

SHRINKAGE AT ONE END.

• TEMPORARY ROPE STAYS CAN BRACE

DURING CONSTRUCTION

OVERALL LATERAL STIFFNESS AND TORSIONAL STIFF-

NESS NOT CALCULATED. DEFLECTION SLIGHTLY EX-

CESSIVE, HOWEVER, CONNECTION STRENGTH WILL

ULTIMATELY GOVERN MEMBER DESIGN.

CHORD PROPERTIES

• LARGE STEEL CAGE ‘GABION BASKETS’

FILLED WITH ASSORTED RIVER STONES

CUT INTO HILLSIDE.

• ABUTMENT A TO BE CUT SUBSTANTIALLY

INTO EARTH TO PREVENT EROSION FROM

RIVER FLOW

• ABUTMENT B NOTCHED INTO ROCK FOR

MECHANICAL ‘KEYING’ ON ABUTMENT

POSITION

1

2

3

4

5

6

A = 8010mm2

E = 12E3MPa