Search results for query: *

Thanks for the info gerhardl

Thank you all for the helpful information The saturated steam service will be delivered to a building for their space heating. The pressure is reduced in the building from 185 psig to 50 psig. The low pressure steam service then goes through a temperature control valve and then to a heat...

Hi Does a butterfly valve for steam service need to have metal seats? Design conditions: Saturated steam, 200 psig and 400F I'm looking at high-performance butterfly valves with the following specs: carbon steel body (WCB), ANSI class 150 to B16.34 (200 psig, 400F) Lug style Not sure if I...

Is there a website I can read about or see examples of?

Is there any specific type or grade of neoprene pad for this application. I guess the strps can be screwed to the top of walls to keep'me in place before lowering the precast lids.

I guess I was just a bit concerned about the contact surfaces between precast lids and top of walls. I'm worried that the concrete finishers don't provide a perfect contact surface and I will have to provide some type of cushion between the two to prevent concrete damages. However, I think using...

Thank you all. all of the comments are helpful

Thanks. Although I know it's ideal to reach the 100% design compressive strength before backfilling/loading but sometimes it's difficult to leave a pit open in the middle of street over a month just for the curing period.

How soon can the formwork for the roof of an underground vault be removed and how soon can loading be allowed on top of it? This structure is an underground vault with dimenstion of 12'x12'x12' with thickness of 10" for all elements w/ 35MPa concrete. Thanks

We are building a 30-foot underground concrete trench box for a utility service with dimensions of 3'x3'. We will have a monolithic pour for slab-on-Grade and walls. The top slabs will be precast and lowered on top of the walls at the end of project. A notch will be provided on top of walls so...

Yes, we will be re-insulating all piping before the pour considering it is high pressure steam line. good insulation may reduce the hot air in the manhole. I guess there will be some ventilation through the opening too. outside temperature could be between 50F to 70F. But if you're saying...

Just to clarify We are replacing a 12-inch top slab with a 10-inch slab (19' x 13')for a steam manhole on existing walls. Live Steam piping within manhole at time of pour. Currently, temperature inside manhole with the existing top slab is about 50 degrees that is why I am assuming the same...

Hi Is it harmful, if freshly poured concrete is subjected to 40 to 50 degrees celcius during its curing period? Does anybody think I should be using retarder in the mix? Thanks guys

cvg, If precast lid is the way to go, is there a waterstop product to be applied to the joint. I can't have water finding its way in the manhole. The reason for the 1 foot thick slab is because the existing slab is 1 foot and also it's out in the roadway with only 2 feet cover but I would go...

Richard One thing about precast for this application is that I won't be able to level off top of existing walls so that the precast lid sit on them nicely.

dicksewerrat How would you attach the preslab to the existing walls?

dik the manhole is used for steam piping, expansion joints and anchors. the walls are in good condition, there is no exposed rebars.

Epoxy coated rebars are to provide protection from underground gas elements and moisture. This is not the only manhole to be in this condition; they are about 40 years old and they contain steam piping within themselves which generates hot air inside despite the ventilation. I believe constant...

Hi Guys, I want to repair an old polygon shaped concrete manhole/vault that is 8' tall. The top slab is in a very bad shape as the rebars are exposed and corroded but the walls and floor slab are fine. I'v decided to replace the top slab by demolishing it and perform an in-place-pour or...