Building lattice towers on ground and pushing them up - still used?

[Alpha]

In earlier days it was common to screw lattice towers especially electricity pylons on the ground and pushing them afterward in vertical position ( see picture) in order to avoid work in great height. Is this method of tower erection still common?

[smurf]

I've never seen it done, but that doesn't mean it doesn't happen. That being said, with the mobility and capacity of today's cranes, there is really no reason to employ that practice. Not only is it more complicated, but that means the tower has to be considerably stronger structurally in a direction that it usually doesn't experience much force. That just means the tower is more expensive, which we all know is a bad thing.

[Alpha]

But this stronger design makes it also more resistant to strong winds. Nevertheless this construction method has a further great disadvantage: the requirement of a large construction site, including a greater clearance to other ropetype structures as powerlines.

[smurf]

Originally Posted by Alpha

But this stronger design makes it also more resistant to strong winds. Nevertheless this construction method has a further great disadvantage: the requirement of a large construction site, including a greater clearance to other ropetype structures as powerlines.

This is true, but wind loadings are considered during the structural analysis, so the gain from this doesn't benefit anything, and only serves to increase the cost of manufacture and erection. It had its day and time, but now that I can rent a 650 ton truck crane, a 550 ton all terrain crane, a 130 ton rough terrain crane or a 2500 ton crawler crane, there is little reason for this method to be used.

[mersar]

Around here they've been actually going away from that design of tower for electricity pylons recently. They've been either going to a supersized steel pole or a bonded wood pole for the high voltage lines. I have seen them assemble a latice type tower a couple years back, they assembled it a small part at a time and then lifted it up and bolted it onto the last part using a crane.

[Alpha]

Lattice towers as electricity pylons are still built in many countries in the world as the erection of a steel tube pylon requires the usage of a heavy crane, which may cause more damage to the ground.

[scalziand]

Originally Posted by mersar

Around here they've been actually going away from that design of tower for electricity pylons recently. They've been either going to a supersized steel pole or a bonded wood pole for the high voltage lines. I have seen them assemble a latice type tower a couple years back, they assembled it a small part at a time and then lifted it up and bolted it onto the last part using a crane.

I've seen this too. When a nearby powerline was expanded, they used poles instead of the lattice towers.

[M.K.]

this only has reason, when cranes are not easy accessible to the site of construction, which is very rare today, among many types of them, load and different systems possibilities like hi-jack. This is a method of ancient times, when cranes were too small. Today all them reach high altitudes, so no reason anymore, and cranes are cheap today.

[Alpha]

Building towers on the ground and than pushing up is still used, see
http://maszt-bud.pl/galeria.html

[Nat]

Originally Posted by smurf

I've never seen it done, but that doesn't mean it doesn't happen. That being said, with the mobility and capacity of today's cranes, there is really no reason to employ that practice. Not only is it more complicated, but that means the tower has to be considerably stronger structurally in a direction that it usually doesn't experience much force. That just means the tower is more expensive, which we all know is a bad thing.

We don't use lattice towers anymore. Ten years ago we built 1000km of transmission line in a remote northern area using structures fabricated from steel pipe and placed by helicopter.

[Alpha]

I believe for tall electricity pylons in remote areas required for crossings of waterways lattice towers would be still a good choice.

[Nowhereman1280]

^^^ Yes, in the US single pole towers are now the standard, but lattice towers are still necessary and used in locations where extra strength or lateral forces are likely to be experienced. For example, they are used very frequently on corners or in places where the cables ascend a steep gradient.

[Alpha]

Lattice towers have still one advantage over pole type towers: the weight of the structure is distributed over a greater area reducing pressure on the ground. Beside this, they can be assembled piece by piece so one does not require too heavy cranes, which cannot be always installed easy on rough terrain.
An interesting question hereby is, how much is the weight of a 20 metres tall pylon built as lattice structure and one of same height for same voltage and conductor arrangement built as pole structure. I believe latter one weighs more.

[John Hinds]

I believe that the newer pole style power lines use considerably less material than the lattice towers, so they should be lighter.



They are also far faster to erect and easier to maintain.

[scalziand]

Originally Posted by John Hinds

I believe that the newer pole style power lines use considerably less material than the lattice towers, so they should be lighter.

[img][/img]

They are also far faster to erect and easier to maintain.

[img][/img]

I'm not so sure the pole towers use less material, but I will agree that they require far less labor for erection and maintenance.

[Sasawest]

I was surprised to see about five years ago a brand new transmission line was being constructed using the lattice style towers located about 30 miles outside of Las Vegas.

[Alpha]

On http://forum.skyscraperpage.com/show...=174510&page=4 you can see how a guyed mast for wind measurement is built in this way.