SAP2000/CSiBridge Bug#1

SAP2000 and CSiBridge are two well-known software that Computers and Structures, Inc. (CSI) develops in the past 30+ years. It aims at resolve finite element analysis problems mainly in the fields of Civil, Structural, and Mechanical Engineering. This series is to address a few bugs I came across when using CSI SAP2000/CSiBridge. Although these bugs are minor and hardly affect your works, I still want to write them down as a note for future reference.

————Let’s Get Started!———————

Bug#1, Incorrect Output of “Volumetric Ratio of Tranverse Confinement Steel” in Section Designer. 

Section Designer is a built-in sectional analysis tool shared by ETABS, SAP, and CSiBridge. With it, users can define a section more arbitrarily and one of its convenient features is to provide confined concrete property based on Mander’s equations that are adopted by Caltrans Seismic Design Criteria (SDC) and other codes.

The outputs that Section Designer provides for a Caltrans confined concrete section are all look good except the ρs, Volumetric ratio of transverse confinement steel to the concrete core.  Please be cautious if you intend to use this number for your subsequent calculation, as it is absolutely wrong. You may have to compute it by SDC equation (3.31).

Except that, I have not found any other error in Section Designer’s output for confined concrete section. And the erroneous output of ρs does not affect other parameters in Section Designer’s output. So it may only be a bug localized for some unknown reason.

bug_section-designer

Reference:

1. Mander, JB; Priestley, MJN. “Observed Stress-Strain Behavior of Confined Concrete”, Journal of Structural Engineering, ASCE, Vol. 114, No. 8, Aug 1988, pp. 1827-1849.

2. Caltrans Seismic Design Criteria, version 1.6, Nov 2010.

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无题

举目唯直终必弯,养狼当犬看家难。
墨染鸬鹚黑不久,粉刷乌鸦白不坚。
蜜浸黄连终需苦,强摘瓜果不能甜。
好事总得善人做,哪有凡人做神仙。

伤情最是晚凉天,憔悴斯人不堪怜。
邀酒摧肠三杯醉,寻香惊梦五更寒。
钗头凤斜卿有泪,荼蘼花了我无缘。
小楼寂寞新雨月,也难如钩也难圆。

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test post

This is a test post…. test :)

state_bent_model

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Hello world!

Welcome to WordPress.com. This is your first post. Edit or delete it and start blogging!

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R Kelly – I Believe

小白的《岩松看美国》的第13集,介绍次贷危机的产生。最后3分钟的片尾曲着实把我感动了。或者说,被自己感动了。
 
 
 
 
                                I Believe — By R. KELLY
 
BARACK OBAMA:
In small towns and big cities
We came together
As democrats, republicans, and independents
To stand up and say that we are
ONE NATION, we are ONE PEOPLE
And our time for changed has COME..
 
R. KELLY:
When the mountain seems too high
And you don’t have the courage nor the strength to climb
And the road you’re on won’t end
But still you run though you cannot see the finish line
 
And dark clouds are over you
Your skies no longer blue
But you marched on straight ahead
Somehow you made it through
 
Got to the mountain peek
They left a path of me
Your victory made history and now
 
CHORUS:
I believe, I believe, I believe
Oh, I believe, I believe, I believe… 

When it felt like you were weak
And couldn’t fight no more
On the ropes and it seemed like
You was gonna run out of breathe
 
When the world was on your shoulder
And the walls were in your way
You leaped and made it over
Through it all you kept the faith
 
With hope you set us free
You showed us how to dream
And now we can lift our voices
And forever sing
 
Now’s the time to look ahead
And thank our hero’s of the past
And celebrate this history
Let’s raise the flag cause
 
CHORUS:
I believe, I believe, I believe
Oh, I believe, I believe, I believe
 
BRIDGE:
And when they tried to keep you down
You kept up your head
Never losing sight
You believed in what was right
 
You endured to the end
Walked through the strongest wind
The storm’s over
And a new day begins
 
And when our hope was dying
You brought us healing
And now I got something
To tell my children
 
CHORUS:
I believe, I believe, I believe
Oh, I believe, I believe, I believe
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Inglewood Earthquake M4.7

Earthquake Strikes! 

最近美国灾事连连,连土地公公也要闹一闹。昨晚8:35,我吃完饭上床小憩,正迷迷瞪瞪的时候,就感觉床开始摇晃。立即把我吓醒了,赶紧下床站住,定定神后就听到窗外(开窗)似乎有大卡车开过的轰隆隆的重低音,仔细听又不是,房子到处都在吱吱嘎嘎响。正担心是不是会有更大的振动时,就感觉振动停了。赶紧上网找USGS的地震报告,居然还没出来,按F5两次后出来了。刚开始报告是5.0级,发生在8:39pm PDT,两个小时后调整为4.7级。震中在Lennox,距离LAX两公里,距离downtown约十五公里。算是我经历的离震中最近的一次地震了。幸好震源深度比较大(15公里)、持时比较短(15秒)。主震后又发生多次余震,我感受到两次,最大一次8:45pm PST,3.1级。捣乱的是著名的Newport - Inglewood断层,这条曾导致了1933年6.4级Long Beach地震的断层可能会诱发最大7.4级的强烈地震。不过这条长约55英里的断层并非著名的有可能导致“The Big One”的San Andreas断层。这是继3月23号里氏3.8级Orange County地震后一个月内南加州第二次有感地震,也是继去年7月29日Chino Hills里氏5.5级地震后南加第二次近似破坏性地震,并进一步显示南加州地震带进入活跃期。
 
【05/19/09添加】5月19日下午3点49分,距离主震第二天后,在几乎同样的地点爆发了强度4.1级的迄今为止最大余震。
参考:
 
 
 
延伸阅读:
下面的视频介绍了San Andreas断层和"The Big One"。
 
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这是最好的时代 这是最坏的时代


It was the best of times,

it was the worst of times, 

it was the age of wisdom, 

it was the age of foolishness, 

it was the epoch of belief,

it was the epoch of incredulity, 

it was the season of Light, 

it was the season of Darkness, 

it was the spring of hope, 

it was the winter of despair, 

we had everything before us, 

we had nothing before us, 

we were all going direct to Heaven,

 we were all going direct the other way- in short, 

the period was so far like the present period,

that some of its noisiest authorities insisted on its being received, 

for good or for evil, in the superlative degree of comparison only. 

———–From Charles Dickens - Tale of Two Cities 

狄更斯在《双城记》的开头说:

“这是最好的时代,这是最坏的时代;
这是智慧的时代,这是愚蠢的时代;
这是信仰的时期,这是怀疑的时期;
这是光明的季节,这是黑暗的季节;
这是希望之春,这是失望之冬;
人们面前有着各样事物,人们面前一无所有;
人们正在直登天堂,人们正在直下地狱。”

[转载自] http://beijing.ifund.jrj.com.cn/forumbeijing/topic97483.html

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