Survey Data Plans required for Bridges

 Survey Maps details 

yogendra borse

The following plans should be submitted for a complete and proper preparation of the bridge project.

1) Index plan (map):-

It should be plotted to a scale of 1: 1000 and should extend to one important town (preferably taluka place or municipal town) on either side of the proposed Bridge.

Index map should show:-

A) the existing bridges along the road.

B) the bridges under construction.

C) other bridges under investigation.

D) the location of the proposed Bridge.

E) other unbridged crossings

F) alternative sides investigated for the proposed Bridge under consideration.

G) the existing as well as proposed Road as per district and Road planning together with their classifications.

H) the general topography of the country.

I) other important towns within the scope of the map.

J) North line (which should be vertical)

2) Catchment area Plan.

    This should be prepared from topo sheets to a scale of 1 mm :1 km and should cover the entire catchment area showing the details of various streams. The plan should be prepared with North line pointing to North that is top of plan.

In case of catchment area about 20 square miles the scale may suitability changed to 1 mm : 4 km.

A reference to all the topo sheets covering the entire catchment should be given so as to facilitate independent checking of the catchment area this should be shown by a grid.

Useful Links to prepare catchment area plan --> Catchment area calculation from Bhuvan and QGIS software

3) Contour survey Plan

It should show all topographical features such as local high spots and depressions etc that may influence the location and design of the bridge and its approaches. 

All sites for crossings worth consideration along with their approach alignment shall be shown on the plan. It shall extend to about 3 m above the highest flood level known or covering a portion of ground equal to twice the river weight on either side of the river which river is less. On the upstream and around stream side of the range of the river within which alternative sides have been recommended it shall extend to the following limits.

A) 100 m for catchment area less than 1 square mile

B) 150 metre for catchment area of 1 to 25 square miles

C) 300 m for catchment area of 26 to 25 square miles

D) 800 m for catchment area above 51 square miles

The contour plan which should be based on cross sections of River. The baseline which should be an enclosed traverse.

Following generally one bank or bad of the river course as may beconvenient and the various cross section LINE which should be generally at right angles to the baseline should be clearly indicated on the contour plan all spot levels taken should be shown correct to one place of decimal only.

Guntur plan should also show

North line

Direction of flow, HFL, OFL, LEL,PTL,LTL etc. Inactive river terraces.

Exact extent of exposed rock, located by offsets from base and cross section lines positions of trial pits or bores.

Boundary of built up area and important buildings nearby and all other permanent stray structures and miles and for long stones on the roads.

Existing Road alignment

Alternative Bridge sites with their approach alignment.

Position of openings of the existing Bridge or causeway if any within the scope of the plan.

Angle of skew of proposed crossing (if any) 

All important BMS their location and values.

The general contour interval should not be more than 2 m for rivers having shallow and white basin with low banks contour interval should be 1 m in the river portion only if not to congested.

Useful Links to prepare Contour Plan --> Contour plan preparation of desired area using Google earth and QGIS software

4) Site plan

In case of stream with a catchment area of not more than 25 square miles this may be combined with contour plan only

It shall be drawn to a scale of 1:200 and shall extend at least 150 m on the upstream and downstream of the range within which alternative sides have been proposed. It shall show the alternative alignments of the approaches for a length of at least 200 m after it meets the existing road in case of big bridges for at least 400 m on either side of the bridge.

It shall show the following details:

A) the name of the stream or bridge and of the road and the identification number allotted to the crossing.

B) the approximate outlines of the bank the high water channel if different from the banks and the lower water channel.

C) the direction of flow of water at maximum discharge and if possible the extent of deviation at lower discharges.

D) the north point

E) the alignment of existing approaches and of the proposed crossing and its approaches.

F) the angle and direction of skew if the crossing is aligned on a skew.

G) the name of the nearest inhabited identifiable locality at either and of the crossing on the roads leading to the site.

H) reference phase 2 the position with description and reduced level of the benchmark used as datum.

I) the lines and identification number of the cross sections and longitudinal sections taken within the scope of the site plan and the exact location of their extreme points.

J) the locations of trial pitts or borings each being given in an identification number.

K) the location of all nalaj buildings wale out crops of rocks and other possible of structures to a road alignment.

L) the soil strata the extent of exposed rock with their changes along the bridge line etc.

M) the position of bores or trial pits.

In case of streams with a gorge width of 150 m and more the following additional information shall be given.

Along the finally selected or recommended alignment a strip of 60 m with that is 30 m on either side of the bridge centre line should be completely charted by a chain and compass survey and plotted to a scale of 1: 40, showing all the silent features falling within the strips such as exact Rock exposures pools or water various soil strata Guntur at 1 m interval Bank lines that is the position of the effective gorge of the river.

The HFL lwl etc this strip should extend along the alignment to 5 m above the HFL and level should be taken at very close intervals say at every 3M or closer at obligatory points. Along the alignment should also be married on this plan.

5) Village map

The village map should be prepared with a North lines so pointing that the diversion that is Road alignment as change and the world runs roughly left to right of the paper that is changed should be progressive from left to right.

This should extend to the same limits as those of the site plan or up to a kilometre aur existing Road beyond divergent points on either side with a minimum size showing an area 3 km long along the road and 2.5 km wide it should show the following details:

A) alternative Bridge sites together with their approach alignments on both banks. Details of curves should specifically Be given.

B) name of stream direction of flow at maximum discharges.

C) angle and direction of skew crossing if any

D) North point

E) exact extend and nature of built up area along the purchase for example kaccha aur pakka structures etc

F) type of the land near the purchase showing the location of wealth if any for example bagayat land or waste land etc.

G) the position of boars and trial pits.

6) cross section of the river at the proposed Bridge site and along approaches.

Tools to prepare above plans