Tiêu chuẩn quốc tế

• Số hiệu / Standard Number: AASHTO HDG CHAPTER 4:2007
• Năm ban hành / Publication date: 2007
• Tình trạng / Status: A - Còn hiệu lực
• Tên tiếng Anh / Title in English: HYDRAULIC DESIGN OF CULVERTS
• Thay thế cho / Replace: AASHTO HDG VOL IV:1999
• Số trang / Page: 50

Phạm vi áp dụng / Scope of standard

INTRODUCTION

The function of a culvert is to convey surface water across or
from the highway right-of-way. In addition to this hydraulic
function, it must also carry construction and highway traffic and
earth loads; therefore, culvert design involves both hydraulic and
structural design. The hydraulic and structural designs must be
such that risks to traffic, of property damage, and of failure from
floods are consistent with good engineering practice and economics.
This chapter is concerned with the hydraulic aspects of culvert
design and makes reference to structural aspects only as they are
related to the hydraulic design.

Structures measuring more than 20 ft (6.1 m) along the roadway
centerline are conventionally classified as bridges. Many longer
structures, however, are designed hydraulically and structurally as
culverts. Culverts, as distinguished from bridges, are usually
covered with embankment and are composed of structural material
around the entire perimeter, although some are supported on spread
footings with the streambed serving as the bottom of the culvert.
Bridges are not designed to take advantage of submergence to
increase hydraulic capacity even though some are designed to be
inundated under flood conditions. For economy and hydraulic
efficiency, culverts should be designed to operate wih the inlet
submerged during flood flows, if conditions permit. At many
locations, either a bridge or a culvert will fulfill both the
structural and hydraulic requirements for the stream crossing.
Structure choice at these locations should be based on construction
and maintenance costs, risk of failure, risk of property damage,
traffic safety, and environmental and aesthetic considerations.
Some of the advantages of culverts are better traffic safety and
lower maintenance costs than bridges. Culverts do not have bridge
railing, which can be a hazard, or a bridge deck, which is subject
to deterioration.

Culverts are usually considered minor structures, but they are
of great importance to adequate drainage and the integrity of the
highway facility. Although the cost of individual culverts is
usually relatively small, the total cost of culvert construction
constitutes a substantial share of the total cost of highway
construction. Similarly, the total cost of maintaining highway
hydraulic features is substantial, and culvert maintenance may
account for a large share of these costs. Improved traffic service
and a reduction in the total cost of highway construction and
maintenance can be achieved by judicious choice of design criteria
and careful attention to the hydraulic design of each culvert.