That's actually a brush with env_lasers on either side of it.

I am talking about this part of the bridge btw http://i.imgur.com/UCBI2b9.png
not about the middle thing (forcefield)

What you want is not a single prop, but a combination of 3 props...
You will need the following 3 props to build it:

1 Base: models/props_combine/railing_128.mdl
2 Uprights (left and right): models/props_combine/combine_binocular01.mdl
2 Heads (left and right): models/props_combine/combine_lock01.mdl

Tip:
To identify a prop...
Load the map, noclip to the prop and put your crosshairs on it, then in the console type: surfaceprop

Wow thanks man that really helped me a lot :D
I got all the props now and I got the bridge almost done but I went in the game to lookup the last prop ( the light bar under it but i couldnt find that one when i typed surfaceprop in console and compared the textures.. :)
http://i.imgur.com/J86yfMF.jpg

The texture used on the edge of the platform is lights/physgunlight, rotated and sized to look like it does in the map.

It is not a prop, but a texture applied to only the 1 face of the platform and sized/rotated.

LOTS of Half-Life 2's best-looking stuff ... is probably brush-based.

ah ok thx guys that all worked :D
But 1 thing this prop http://i.imgur.com/CXfZRCe.png I placed but when I start up gmod to test the map then its not there D:

Try changing the prop type: static/dynamic/physics

Ok thanks ill try that when im home from work :p
What is the difference tough? :p

Best explained here:
https://developer.valvesoftware.com/wiki/Prop_Types

If a prop's model is not meant to be used as the type you have it set to it may not show up.

Thank you so much for your help my bridge is finished now :)
Result: http://i.imgur.com/1zUaE7d.jpg
Btw is there any way (like surfaceprop) to see what lasers are these? http://i.imgur.com/pOLI6Kx.jpg

Nice job on the bridge!

You can always open a bsp that has what you're looking for in notepad++ or another utility, don't make changes or alter the file, but you can usually find the info needed to recreate.

Not positive but I think the lasers are env_beam with materials/sprites/physbeam.vmt for the sprite and the beam color set to 158 219 248