Building a 10m x 2m Steel & Concrete Footbridge

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Discussion Overview

The discussion centers around the design and construction of a 10m x 2m footbridge made from steel and concrete, including considerations for foundation design. Participants are exploring various aspects of the project, including load requirements, materials, and structural integrity.

Discussion Character

  • Technical explanation
  • Debate/contested
  • Homework-related

Main Points Raised

  • One participant requests ideas for designing a footbridge over a river, specifying dimensions and materials, and mentions relevant borehole data.
  • Another participant questions the necessity of a concrete and steel bridge and suggests a clearer phrasing of the dimensions.
  • Several participants inquire about functional requirements, load-bearing capacities, and suggest estimating loads based on the maximum number of users.
  • One participant proposes using two steel I beams supported by concrete abutments, emphasizing functionality over aesthetics.
  • A suggestion is made to create a cross-section of the stream valley to better understand foundation placement and effective span.
  • Another participant emphasizes the importance of listing required features and determining various load factors, including environmental considerations and building codes.
  • Discussion includes the need for assumptions regarding bridge size and the potential impact of groundwater on foundation design.

Areas of Agreement / Disagreement

Participants express various viewpoints on the design requirements and considerations for the footbridge, with no consensus reached on specific approaches or solutions. Multiple competing views on the necessary features and load calculations remain evident.

Contextual Notes

Participants note the importance of understanding the borehole data in relation to the stream section and the need for assumptions in the design process. There are unresolved aspects regarding the exact load requirements and structural calculations.

bigtam
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hey ppl,
In a nutshell, need to come up with a 10mX2m foot bridge over a river made from steel and concrete

also to include foundation design.

borehole data are as follows.

Depth. Description

0.2M Topsoil
2.60M Loose silty sand
4.56M Boulder clay

water was met 1M below ground level.

any ideas?

trying to work to BS4 prt1 2005
trying to take into account that a max of 10 people maybe on this at one time.

Thanks guy's
 
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Looks like coursework?

So what are your initial ideas?
 
bigtam said:
hey ppl,
In a nutshell, need to come up with a 10mX2m foot bridge over a river made from steel and concrete

also to include foundation design.

borehole data are as follows.

Depth. Description

0.2M Topsoil
2.60M Loose silty sand
4.56M Boulder clay

water was met 1M below ground level.

any ideas?

trying to work to BS4 prt1 2005
trying to take into account that a max of 10 people maybe on this at one time.

Thanks guy's

My apologies for this but I can't resist. Why do you need a bridge over a stream made of concrete and steel?
I am aware that English my not be your native tongue, in English we need to get the adjectives next to the word they describe. Perhaps;
" 2mX10m steel and concrete bridge over a river" is what you mean.

Sorry for the distraction.
 
does it have a requirement for functionality or minimum weight bearing or anything like that? if not it's just like drafting and u can draw any bridge u want... >_>
 
quantumdoodle said:
does it have a requirement for functionality or minimum weight bearing or anything like that?

"trying to take into account that a max of 10 people maybe on this at one time." Assume 100kg a person (to be safe, 225lbs) or more would give you a load estimate.

Do you have any ideas where to start?
 
Studiot said:
Looks like coursework?

So what are your initial ideas?



Well for a starting point,
using two steel I beams as the main support ontop of a concrete abutment at each end.

Aiming for more functionality as apposed to aethstetic's.

unsure where to start for the calculations to be honest.
(trying to factor in hand rails and decking also but unsure on BS on the overall bulding of this)
 
Well I would start with a X section of the stream valley.

Your borehole data is useless without relation to the section.

Then you can roughly locate the foundations on the section.

Then you can get the effective span.

Then I would get a rough idea of the foundation loads = foundation weight + dead + super dead + live. (times partial factors as set out in the BS)
Assumptions about the size of the bridge would need to be made for this.

This will give you foundation pressures so you can design the foundation areas to suit.
You may have to take the founds lower to avoid undercutting by groundwater or the stream. Again this is why you need the section.

This should get you started.
 
bigtam,

Another way to start might be to list all the features you think are required. Then arrange them in order of importance.

Certainly from an engineering point of view you need to determine the loading: people, snow, wind, seismic, and whatever else, handrail loads from people, vehicles. Most of that is usually dictated by a building code. I can be argued that "correctly" determining the load requirements is more challenging than the design of the bridge itself.

In terms of a beam or bridge span remember that depth is a key, and note that handrails are usually 3 feet high, take advantage of that if you can.