AASHTO R 8-96(2015)

VIP免费

老杨树 2024-10-25 10 847.62KB 14 页 15星币

侵权投诉

Standard Practice for

Evaluation of Transportation-

Related Earthborne Vibrations

AASHTO Designation: R 8-96 (2015)1

American Association of State Highway and Transportation Officials

444 North Capitol Street N.W., Suite 249

Washington, D.C. 20001

TS-5b R 8-1 AASHTO

Standard Practice for

Evaluation of Transportation-

Related Earthborne Vibrations

AASHTO Designation: R 8-96 (2015)1

1. SCOPE

1.1. This standard practice is to provide guidance for the assessment of potential or alleged structural

damage due to earthborne vibrations related to transportation facility construction, maintenance, or

operation.

2. INTRODUCTION

2.1. The construction, maintenance, and operation of transportation facilities generate vibrations,

which are transmitted through the air and earth and are subsequently received or “sensed” by

structures or inhabitants. Only earthborne vibrations are addressed in this standard practice (see

Section X2.8, Appendix X2).

2.2. Currently accepted practice in monitoring earthborne vibrations considers two parameters―earth

particle velocity and wave frequency―determined at the site of concern (Siskind et al., 1980; see

Figure 1). Sensing instruments are usually set out on the ground adjacent to the subject structure.

For determination of safe vibration control limits, special concerns may dictate placement of

sensors directly on specific parts of a structure such as the foundation, a supporting column,

or a wall.

2.3. Much of the data concerning structural damage have been determined from blasting activities.

Blasting is a commonly used construction-related procedure that produces vibrations characterized

by a wide frequency range and potentially high intensities but of very short duration.

Transportation-related activities, such as vehicular or rail traffic, may be the source of repetitive,

cyclical vibrations of much lower intensity than those caused by blasting. There may be concern in

this regard because of potential for fatigue of structural components. Documentation of specific

damage due to such transportation-related vibrations is scarce (Whiffin and Leonard, 1971;

Ames et al., 1976).

2.4. People “sense” or respond to a much broader range of vibration frequencies and intensities than do

structures. Intrusive vibration levels can annoy humans at much lower intensities than levels

considered critical for structures (see Figure 2). Such sensitivity causes concern for structural

damage potential even at the extremely low levels of vibration that are a recognized nuisance to

people. Various threshold limits have been recommended in standards aimed at minimizing

damage to various structures. Recommended safe vibration limits are based upon the appearance

of “threshold cracks” or cosmetic cracking. Such cracks appear at lower vibration levels than do

architectural or minor damage. The applicability of specific limitations is often the subject of

litigation requiring expert witness opinion.

TS-5b R 8-2 AASHTO

Figure 1—Safe Vibration Limit Recommendations for Residential

Structures (USBM RI 8507)

2.5. Concerns of anticipated or perceived damage can be related to structures or their contents.

Practically all buildings contain fine cracks or imperfections that are not noticed until concern

is stimulated by perception of abnormal vibrations. Evaluation of the potential effects of

transportation-related earthborne vibrations requires documentation of the background or

pre-existing condition of the structure or component of concern. Such an evaluation should also

include a determination of the intrusive vibration characteristics (amplitudes and frequencies) at

the point of interest. Dowding (1992) reviews the various methods for determining ground

vibration frequencies. Analysis of the results may necessitate modification at the vibration source

or mitigation of effects at the location of concern.

3. PROCEDURE

3.1. A survey of the site should be made by personnel capable of locating, evaluating, and

documenting significant or apparent evidence of distress. Such surveys preferably should be made

before the onset of any objectionable vibration-producing activity. The scope of the inspection

should be appropriate for both the subject of concern and the intensity of the vibrations.

Photographic or video documentation of the inspection is recommended. Any procedures

requiring intrusion on property should be specifically permitted by the property owner, preferably

in writing. Specialists in vibration monitoring are often contracted for survey services.

Frequency (Hz)

Particle Velocity (in./sec)

0.75 in./sec

Drywall

2 in./sec

0.008 in.

0.03 in. 0.50 in./sec

Plaster

0.1

0.01 110100

文档加载中……请稍候！
如果长时间未打开，您也可以点击刷新试试。

下载文档到电脑，查找使用更方便

亲，本站95%以上的标准规范都面向会员免费，办理VIP会员下载更省钱，平均每篇不到2元

立即下载 VIP免费下载

摘要：

AASHTO R 8-96(2015) 是美国国家公路与运输协会（AASHTO）发布的一项标准规范，全称为“Standard Practice for Evaluation of Water in Concrete Mixes”（混凝土拌合物中水评估的标准实施规程）。该文件最初于1996年制定，并在2015年进行了确认与重新批准，旨在为混凝土施工中水含量的评估提供统一、可重复的试验与判定方法。通过对混凝土拌合物中实际用水量的准确测定，该标准有助于确保水灰比的控制，从而保障混凝土的强度、耐久性与工

展开>> 收起<<

AASHTO R 8-96(2015).pdf

共14页,预览4页

还剩页未读，继续阅读

声明：本文档系会员上传，若文档所含内容侵犯了您的版权或隐私，请立即通知，我们立即给予侵权申诉删除！

AASHTO R 8-96(2015)

相关推荐

开通VIP享超值会员特权

相关内容

热门标签

举报选择: