Dayexco-
we've been sharing in a post on General topics regarding shallow digging/utilities.
A post you made stated:
"last week we were installing a 10" sanitary sewer main 13' deep in a development. in the alley we approached, we encountered a cable tv wire, 3' away, a competitor's cable tv wire, 3 ' away a telephone cable, 3' away a 4" gas main, 3' away a primary power cable...try getting a trench box under that, an excavator bucket in between them, compaction equipment around or underneath them...a real headache. proper planning on their part would have put all the wires in one duct bank or trench, and the gas line 3' away from that, making only 2 items to jump, work around.
it's really getting to be a headache in my neck of the woods with this problem. any of you encountering the same? "
Under this Centering Catch Basin thread, you question if compensation should be considered unless possibly mob/demob is involved or financial burden incurred.
I would contend that the utility situations you mentioned in General above listed thread are significant financial burdens to your firm incurred due to time and overhead expended doing "dirt surgery" around them. Do you guys go into a job with a "bump up" factor in bid (and thus risk not getting the project in low bid scenarios!) for "unforseen" utility situations. If so, how do you quantify such (please forgive me- i'm not trying to pry into your company's strategic decisions here)?
We are not allowed in Texas One Call Law to request locates for utilities for design work-only construction. Thus as the contractor i'm at the mercy of the engineering firm/owner to give me a "clear" job or show no utilities whatsoever on the plans and let me take my chances. If they show a partial utility locations on plans, am I not bound contractually that's what's in the ground? And if I find utilities that even the owner/operators of the utilities don't know about, do those things not also affect the critical path?
Being long winded here- please don't think i'm being confrontational, but rather trying to understand construction contracts around the U.S. I do understand that there's a relational balance with owner and engineer and that actions today may have adverse (or positive!) reactions 5, 10... years down the road in terms of business relationships. I suspect this depends on the project, but does your company have any general rules of thumb related to how much delay/overhead overruns you'll accept on a job before requesting change orders?
Returning to focus on Jim's last 2 points:
1. On DOT projects here in my area of TX (at least the ones i've seen), all that exists prior to construction staking of the proposed roadway are a series of "H" points (hubs on the ground- and not necessarily on the roadway CL). TxDOT specification i believe requires points spaced no greater than every 1500'. All points have an XY (or NE if you prefer that nomenclature) and an elevation. They are the primary control from which all existing and proposed features are developed. One other post mentioned 2 points and i suspect that works pretty well although additional points provide redundancy in the event of destroyed primary control and for additional construction staking checks.
HOPEFULLY, your engineering firm which designed the job will post enough data in the plan set to layout any feature of the project by merely reading the plans. I submit that many firms do not have engineers with enough "trench time" to understand your particular needs for staking etc. This goes back to the education of surveyors (and engineers!) that Dayexco and others stressed.
Most jobs today are semi-complicated and more detailed due to computer aided drafting and design software. One reply indicated a desire to perform staking himself in lieu of the surveyor. I concur, as i think it makes me a better contractor as well as civil engineer. However, obvious risk is applied to our shoulders in this situation and that level of risk will be different for each company. Also requires me to brush the dust off the old trigonometry books from school!! Anyway,some folks want to move dirt, not survey, and i respect that.
Given the horizontal control of the job, some location feature of your basin can be given an XY coordinate in space (in the designers CAD file). If the roadway has a horizontal alignment on the plans (CL alignment), trigonometry provides us with a station and offset to that point of interest on the basin.
I cannot answer specifics about your particular curb offset situation, but for any point i need to lay out on the job, the following is true to my knowledge:
I can set a total station on a known xy coordinate and backsight another known xy coordinate (how convenient that the "H" points are there for me!). This establishes a 0 bearing line . If i know the desired XY coordinate of the point to lay out (CL basin, 10' o/s hub, corners of box, etc...), trig gives me the angle i need to turn with the gun and also the distance along that angle that i need to pull from the pin that the instrument is on to lay out the point.
We always attempt to get cadd files from engineering firms for jobs to assist us in the development of construction staking in the event that the plans might lack a station/offset or two. However, the cadd files are merely a supplement, not to replace, the paper plans. Having the cadd files often allows us to check xy's or sta/offsets provided by the engineer prior to our stakeout-not to take the responsibility off the designer, but as one post indicated, we might be able to find something in the plans that helps us to be a better "partner" on the job.......
i apologize for being long-winded
