php อยากให้คอลัมน์ Hour ที่เก็บข้อมูลเป็นเวลามาบวกกันค่ะ

$timestring = array("838:59:59","838:59:59","838:59:59");
$timeCalculate = array('hr'=>0,'min'=>0,'sec'=>0);
foreach($timestring as $time){
    $timeshift = explode(':',$time);
    $timeCalculate['hr'] +=$timeshift[0];
    $timeCalculate['min'] +=$timeshift[1];
    $timeCalculate['sec'] +=$timeshift[2];
}
print_r($timeCalculate);
$timeCalculate['min'] += floor($timeCalculate['sec']/60);
$timeCalculate['hr'] += floor($timeCalculate['min']/60);
$timeCalculate['min'] = $timeCalculate['min']%60;
$timeCalculate['sec'] = $timeCalculate['sec']%60;
echo "<br />";
print_r($timeCalculate);