Tiêu chuẩn quốc tế

• Số hiệu / Standard Number: AASHTO HDG CHAPTER 9:2007
• Năm ban hành / Publication date: 2007
• Tình trạng / Status: A - Còn hiệu lực
• Tên tiếng Anh / Title in English: STORM DRAIN SYSTEMS
• Thay thế cho / Replace: AASHTO HDG VOL IX:1999
• Số trang / Page: 98

Phạm vi áp dụng / Scope of standard

INTRODUCTION: The highway facility should be designed to be
compatible with existing drainage patterns. Concurrently, the
highway and the traveling public should be protected from the
hazards of flooding. In this regard, the drainage design for the
highway facility has a threefold purpose:

□ prevent adverse interference to the existing drainage,

□ protect the traveled roadway surface from certain flood
events, and

□ provide for the removal of water from the roadway subgrade and
the embankment.

Storm drain system design should recognize that floodwater
reaches the highway right-of-way in three main ways:

□ precipitation falling within the right-of-way;

□ stormwater that flows onto the right-of-way as surface or
overland flow;

□ stormwater that comes to the highway in a defined watercourse.
Water in a defined watercourse is usually conveyed as
cross-drainage. In such cases, a primary design objective is to
pass stormwater through the highway embankment without adverse
effects to the highway or to the property on either side. Guidance
for the design of cross-drainage facilities is contained in
Chapters 4 and 7 (4, 7)1 and HDS 5 (39).

Although stormwater approaching the highway in a defined
watercourse may be accommodated in a storm drain system, the
primary concern of this chapter is floodwater from rain falling
within the right-of-way and from overland flow. Guidance is given
on how storm drain systems can be designed to collect, convey and
discharge stormwater flowing within and along the highway
right-of-way. This chapter covers most types of highway drainage
excluding cross-drainage as defined above and most types of highway
drainage facilities excluding culverts and bridges.

Storm drain systems include elements such as:

□ pavement drainage,

□ inlets,

□ storm drains,

□ roadside drainage channels,

□ stormwater storage facilities,

□ systems for draining subsurface water,

□ siphons,

□ pumping stations,

□ outfalls,

□ water quality facilities, and

□ hazardous spill containment systems.

In addition to discussion on the design of these elements, this
chapter also discusses various factors affecting storm drain system
design, computer modeling of storm drains, documentation and
considerations pertaining to construction and maintenance.

Serious consideration and application of the subjects discussed
in this chapter can have a positive effect on the efficiency,
safety and cost of highway storm drain facilities.