Permanent Signs Mounted on Median Barriers (2014) / Chapter Skim
Currently Skimming:
Pages 14-23
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 14... ...
12 CHAPTER THREE EXISTING SIGN AND BARRIER COMBINATIONS The primary objective of the synthesis study was to gather, compile, and disseminate information describing current practices for mounting permanent signs on rigid median barriers throughout the United States. A majority of the information was gathered from responses to a survey questionnaire that was distributed to all voting members of the AASHTO Subcommittee on Design, which includes representation from all 50 state DOTs and the District of Columbia DOT.
|
From page 15... ...
13 ing information on median-barrier-mounted applications, the survey questionnaire did not differentiate between span/ bridge and cantilever supports. Question 3 of the survey asked agencies approximately how many existing overhead sign supports, mounted within or on top of rigid median barriers, are installed throughout their agency's total divided highway network.
|
From page 16... ...
14 Ten agencies reported vertical tapering of the top of the barrier profile in the vicinity of the sign support. This treatment is more applicable to barriers less than 42 in.
|
From page 17... ...
15 Five agencies reported attaching metal beam rail to the traffic face of the barrier in the vicinity of sign supports to reduce vehicle climb during impact and thereby reduce the size of the ZOI. This treatment is shown in Chapter 6, Figure 6-12 of the AASHTO Roadside Design Guide and is used extensively in at least one state to increase protection against impacting bridge piers that are immediately behind rigid barriers.
|
From page 18... ...
16 2. Saddle-style base plate that is bent to straddle the top of the barrier with various anchor bolt configurations: horizontal bolts that extend through the barrier, with nuts on both sides; horizontal expansion or adhesive anchor bolts extending into the barrier from both sides; or a combination of horizontal and vertical anchor bolts.
|
From page 19... ...
17 FIGURE 6 Typical details of small sign supports mounted on rigid median barriers.
|
From page 20... ...
18 the types and sizes of posts cover a wide range, as shown in Table 5. U-channel and perforated square tubes are the lightest, and the weight range progresses up through various structural shapes.
|
From page 21... ...
19 between median barrier sections to eliminate the need for additional supports. Several agencies stated that they either prohibit or are phasing out median-barrier-mounted sign supports unless no other option is available.
|
From page 22... ...
20 the "None" category, comments primarily related to not needing special treatments because the standard barrier is presumed to be high enough to sufficiently reduce the ZOI or the agency simply does not allow median-barrier-mounted sign supports. The five toll road authorities that responded to the survey questionnaire reported using some of the same practices used by DOTs.
|
From page 23... ...
21 is to eliminate the need for barrier-mounted sign supports by moving the signs. Two toll road authorities reported having 500 to 999 small sign supports installed on rigid median barriers within their jurisdiction.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.